Anne's preoccupation with death begins with her loss of faith in God at age fifteen. The account reflects the author's experience as told later in Memoirs of a Dutiful Daughter (1959). It follows the same pattern, namely, a temporary relief from the metaphysical fears through the heroine's love for a man. However, the end of Anne's affair with the American writer Lewis Brogan triggers again her acute fear of aging and suffering and her painful awareness of her mortality. The obsession with death affects her relationship with others and pervades all aspects of her life. She contemplates suicide at one point, but does not carry it out because of her love for her family.

In The Mandarins, Beauvoir develops two contrasting themes: that of the finitude of man with its contingent fear of aging and obsession with death as illustrated in the attitude and actions of its heroine Anne; and the opposing theme of optimism, with its inherent positive attitude geared toward action, which runs parallel throughout the novel and is embodied in the protagonist Henri Perron.

In Force of Circumstance the author states that in The Mandarins she used the theme of repetition in "the Kierkegaardian sense" to show the impasse in which the protagonists find themselves. In the case of Henri and Dubreuilh this theme can be seen in the loss of their friendship, the subsequent renewal of this friendship, unresolved differences notwithstanding, and in the heroine's case, three trips to visit her lover in America and her final return and resolve to remain with her husband, also without having overcome her fears and obsessions which had initially been her reason for taking a lover. In short, at the end of the narrative, the characters find themselves at their point of departure.

Another theme developed in The Mandarins is that of the privileges enjoyed by the bourgeois class to which belong "The Mandarins." This is not an isolated theme in Beauvoir's work; it is discussed in her autobiographical writings as well as in her works of fiction.

Among the minor themes explored in The Mandarins is the relationship between mother and daughter which reappears later in Les Belles Images (1966) and A Woman Destroyed (1967). This theme is discussed at length in The Second Sex (1949) and developed in detail in Beauvoir's autobiographical writings. In The Mandarins, the heroine Anne, a psychiatrist, trained to help others, deplores not being able to do the same for her daughter Nadine, an ill-adjusted, rebellious nineteen-year-old. Anne blames herself for Nadine's troubles, believing that she had not known how to love her daughter. She later has to recognize that Nadine has found her own way, regardless of what she, her mother, did or failed to do.

Another minor theme in many of Beauvoir's works is woman's emotional and, often, financial dependency on a man. For a woman to give up her professional life in order to devote herself entirely to her husband or lover and live vicariously through him, is seen as self-destructive.

Beauvoir's intent in writing The Mandarins had been to portray postwar France, the hopes and subsequent disillusionment of leftist intellectuals about the fact that the bourgeoisie with its privileges had emerged unscathed and stronger than ever from the debacle of World War II. Yet, Beauvoir did not produce a strictly historical novel; her personal themes and obsessions remain at the center of her fiction. Beauvoir's skillful interweaving of the public and private lives of her characters allows her to explore political themes. Henri's position as journalist and Dubreuilh's stature as politician are ideal for the purpose of introducing the themes of commitment, political compromise, party loyalty, and personal responsibility.