I agree with all of the previous answers that state the oldest form of writng (cuniform) is attributed to the ancient Sumerians of Mesopotamia 3200 B.C.E. However, recent archaeological discoveries in Egypt by Gunter Dreyer, German Archaeological Institute in Cario might tell a different story. The small tags he found in the tomb of King Scorpion I date from 3400-3200 B.C.E. suggesting that there might be a two hundred year window that could possibly change the answer to your question, which is why your question is so important to human history. It is vital that those who study our human origins through historical method continue to measure their evidence with that of the archaeological evidence. The quest to understand and correctly document the human experience is ever changing, therefore new information/evidence that has academic merit should always be acknowledged.
The beginning of writing has its inception in "hash marks" used for counting by people living 50,000 years Before Christ (B.C.). These marks slowly took on more complexity. By 4,000 B.C. the marks had gotten very complex and were used to convey detailed bits of information. In the Indus Valley, some peoples were using such marks to decorate pottery but the marks didn't convey enough cohesive information to be qualified as writing. Writing is defined as an organized and consistent system of graphemes that conveys both concrete and abstract information [grapheme: the minimal unit of a writing system (a, b, c, etc)]. The first to develop such a system were the Sumerians who developed an organized system of graphemes to use in taxation transactions to keep information organized in such a way that all participants in a taxation transaction knew the same things and could agree to the same actions and outcomes. From this beginning, the whole Sumerian writing system developed that later met the definition of an organized system of graphemes for conveying both concrete and abstract information.
[For more detail, see the article "The Invention of Writing" at Erasmatazz.com from which this answer is drawn.]
We do not know this for sure, because some culture might have been writing on wood or papyrus or something and its writings could have been lost because they rotted. However, the first writing we know of was invented by the Sumerian culture of Mesopotamia. This writing was done with a stylus on wet clay. It is known as cuneiform. The word "cuneiform" means "wedge-shaped." This term is used because that is what shape the characters generally were.
This type of writing was being used as long as five thousand years before the present time.
Writing has developed with as a series of innovations and and improvement, that took place over a period of around 20,000 years, in ways of representing information in form of pictures and symbols made on plain surfaces. Perhaps, thousands of people from different parts of the world have contributed such development, in prehistoric and ancient era. There are no historical evidence available to to identify any one person or even a small group of person as inventors of writing.
The origin of writing can be seen in drawings made on walls of caves, more than 20.000 years back to describe some events. Writing of this type conveyed meaning without depending on knowledge of any particular language. Many scholars believe that writings that depended use of symbols defined by a system of language were first developed by Sumerians around 3500 B.C. This system of writing called cuneiform was very complex with use many symbols that represented words and syllables. Earliest system of writing using a system of alphabets is believed to have been developed by Semites around 1500 B.C.
In many ancient communities, writing had an important role, especially since the writing system was known only to certain people. They were considered privileged and keepers of the gift of the gods. Egyptians, Mayans, Chinese, everyone saw writing as a gift from God. Thus, the invention of writing was attributed, by the ancient Egyptian,to the god named Thoth, who had given them the arts and sciences,for the Sumerians, writing was a gift given by the god Enlil, while for the Mayans, shaman and Itzamna wizard were creators of the world and writing.So who knew the secret of the gods was privileged, and sometimes, in this respect, was superior even to leaders.
The modern world has decided: writing weren't given to us by the gods, but it was invented by humans, and its invention was made independently, in places like China, Mesopotamia and Mesoamerica. Recently Europe entered in books, struggling for recognition as the place where writing was invented long ago.
At first, people scratched on the walls of caves, but in time turned to other media that can be transported. Thus, occured the notes on clay tablets, on the bone or tortoiseshell.
The ancient civilizations of Mesopotamia,are fighting for a podium place on the older writing systems. The oldest examples of writing from Mesopotamia is dating from IV millennium BC, but apparently cuneata records on various media have been made much earlier: the adhesive tablets were used by communities in Mesopotamia since 8000 BC.
The tablets used were simple (revealed in today's Turkey, Syria, Israel and Jordan), but others, were more complicated, where writing was decorated with all kinds of signs.These small plates, in their evolved from, occurred only in IV millennium BC. AD and it seems that they were used to record trade. Tablets were stored either in "envelopes" made from clay, or they were connected with thick twine.
And the Chinese have proved to be inventive, but one thing should be noted: the Chinese system of writing was registering little changes in 3500 years of evolution.The oldest forms of Chinese writing were found on the frog shell and animal bones, being dated between 1500-1000 BC. Their features? Pictographic symbols, that are stylized representations of the objects that they represent. Later, the Chinese have placed their notes on bronze vessels and some of the oldest forms of writing are used today when it comes to art of calligraphy.
For the V-VI centuries BC, the Chinese have started to harmonize the system of writing and to remove variations in different regions, so outlined then writing has been preserved until today , only in the twentieth century it was less simplified.
Complex proved to be the system of Egyptian writing,so hieroglyphics scratched were known only to few people: the scribes or members of religious orders.Therefore, often, even all Pharaohs were not aware of the writing system. So, in addition to hieroglyphics, the Egyptians developed simpler writing systems : hieratic, used by priests, and Demotic, used by ordinary people.Among the oldest inscriptions in hieroglyphs are those known as Narmer and dated to around 3200 BC.
The Latin alphabet is the most widely used system of writing and is dated around 700 BC.