The greatest difference between competitive intelligence and espionage is that competitive intelligence is legal and espionage is illegal. Competitive intelligence refers to the gathering of all relative information (products, customers, and competitors) in order to help organizations and business make tactical decisions. This type or intelligence is normally used to foresee any problems or risks which may arise before they arise. Most times, this information is gathered from public sources or given freely by other organizations or businesses.
Espionage, on the other hand, involves the attainment of classified (secret or confidential) information. The person obtaining the information has no right to the information. Obtaining the information could include falsifying information about who one is (in order to gain access to the desired information) or bribing (with money or promises) people who are already working within the company or organization.