The meanings of sexuality in seniorhood are found at the base of a complex interrelation between social, cultural and personal factors. The present research aimed to explore the psychological meanings that senior adults in Mexico City confer on sexuality, sexual pleasure and sexual desire; through the use of modified natural semantic networks. The sample consisted of 204 people: 162 senior women and 40 senior men, between 60 and 100 years old, attending a continuing education centers for senior adults in Mexico City. The study was mixed, descriptive, non-experimental, with non-probability and convenience sampling. The results show how the psychological meanings that the studied senior adults have related to sexuality, desire and sexual pleasure are predominantly positive, encompassing feelings, behaviors and sensations. Differences by gender are identified as proposed in the research hypothesis, but similarities within these meanings were also found. The senior women studied define sexuality from the interrelation between affective meanings and physical contact; the word "love" was the most referenced. In addition, they mentioned "pleasure", "desire", "caresses", "satisfaction", "kisses", "joy", "hugs", "health", "attraction", and "knowledge". Senior men, for their part, consider sexuality mainly as an attraction and include others such as: "satisfaction", "pleasure", "respect", "life", "fidelity", "complete", "unique", "woman", "touch", "important", "love", "knowledge", "passion", "desire", "need", and "affection". Women and men in the sample describe sexual desire and pleasure in a very similar way to their sexuality referents, which leads us to understand that the boundaries between the two terms are sensitive. Regarding sexual desire, senior women cite defining words such as: "caresses", "kisses", "love", "hugs", "pleasure", "desire", "necessary", "satisfaction", "natural", "attraction", "partner", "happiness", and "respect". In relation to sexual pleasure, they include the words: "enjoyment", "tenderness", "affection", "friendship", "joy", "it is the maximum", and "relaxing". For their part, senior men defined sexual desire as: "attraction", "love", "caresses", "satisfaction", "looks", "necessary", "natural", "woman", "kisses", "being alive", "respect", "passion", "libido", "important", "moving", "pleasure", "hug", "energy", "games", "excitement", "communication", "masturbation", "eroticism", and "taste". Sexual pleasure includes: "important", "fullness", "enjoyment", "respect", "pleasure", "joy", and "naturalness". The results show that the stage of sexuality in seniorhood is diverse and it is influenced by gender and social beliefs, which evidences the psychological complexity of this sphere of life. [ABSTRACT FROM AUTHOR]