As most epidemiological surveys on sexual problems have not included assessment of associated distress, the principal aim of this study was to provide prevalence estimates of both DSM-IV-TR-defined (American Psychiatric Association [APA], 2000) and less commonly assessed sexual difficulties and dysfunction (e.g., lack of responsive sexual desire, lack of subjective arousal). A secondary aim was to obtain information about comorbidity between sexual desire and sexual arousal difficulties/dysfunction. This study comprised an online survey completed by 35,132 heterosexual Flemish men and women (aged 16 to 74 years). Results indicated that sexual dysfunctions were far less common than sexual difficulties,and some uncommonly assessed sexual problems (e.g., ‘‘lack of responsive desire’’ in women;‘‘hyperactive sexual desire’’ in men) were quite prevalent. In women, there was a high comorbidity between ‘‘lack of spontaneous sexual desire’’ and ‘‘lack of responsive sexual desire’’;between ‘‘lack of genital arousal’’ and ‘‘lack of subjective sexual arousal’’; and between sexual desire and sexual arousal difficulties/dysfunctions. The implications of these findings for epidemiological research on sexual dysfunction and for the newly defined DSM-5 Female Sexual Interest/Arousal Disorder (APA, 2013) are discussed. ; status: published