The evolution in conceptualization of sexual desire has stimulated many attempts to measure it. However measures able to assess multiple expressions of desire in all sexual identities are still lacking. The main aim of the present study was to test the psychometric properties of the Sexual Desire and Erotic Fantasies questionnaire - Part 1 Sexual Desire (SDEF1), developed as a sex-positive measure of different sexual desire expressions. The SDEF1 was assessed in 1773 participants from the Italian general population (1105 women, 645 men, and 23 other genders; ranged between 18-78 years old, mean age 29.31 ± 10.35) on an online survey, together with the Sexual Desire Inventory - 2, the International Index of Erectile Function, the Female Sexual Function Index, and the Marlowe-Crowne Social Desirability Scale-Short Form. Results support a factorial structure of six dimensions, including 28 items and accounting for 58.11% of the total variance: sexual desire, negative feelings to sexual desire, autoerotic desire, regular partner desire, attractive person desire, and responsive desire. The confirmatory factorial analysis showed satisfactory indexes (RMSEA = 0.042 [90% CI = 0.039-0.045]; GFI = 0.97; NFI = .96; and CFI = 0.97). Regression coefficients ranged from 0.39 to 0.94 and were all statistically significant (p < 0.001). The SDEF1 showed good psychometric properties such as internal reliability, construct, and discriminant validity, and to differentiate women and men with and without sexual difficulties. Men reported significantly higher levels of desire than women in all areas except for desire for a regular partner, were no gender difference was detected. Desire for autoerotic activity was the factor accounting for more variance explained among genders (11.7%). The SDEF1 could be a useful measure to assess different areas of sexual desire and its use could be recommended for clinical and research purposes.