BACKGROUND: Sexual dysfunction (SD) is an important underestimated adverse effect of antidepressant drugs. Patients, in fact, if not directly questioned, tend to scarcely report them. The aim of the present meta-analysis was to quantify SD caused by antidepressants on the basis of studies where sexual functioning was purposely investigated through direct inquiry and specific questionnaires. METHODS: A literature search was conducted using MEDLINE, ISI Web of Knowledge, and references of selected articles. Selected studies performed on patients without previous SD were entered in the Cochrane Collaboration Review Manager (RevMan version 4.2). Our primary outcome measure was the rate of total treatment-emergent SD. Our secondary outcome measures were the rates of treatment-emergent desire, arousal, and orgasm dysfunction. RESULTS: Our analyses indicated a significantly higher rate of total and specific treatment-emergent SD and specific phases of dysfunction compared with placebo for the following drugs in decreasing order of impact: sertraline, venlafaxine, citalopram, paroxetine, fluoxetine, imipramine, phenelzine, duloxetine, escitalopram, and fluvoxamine, with SD ranging from 25.8% to 80.3% of patients. No significant difference with placebo was found for the following antidepressants: agomelatine, amineptine, bupropion, moclobemide, mirtazapine, and nefazodone. DISCUSSION: Treatment-emergent SD caused by antidepressants is a considerable issue with a large variation across compounds. Some assumptions, such as the inclusion of open-label studies or differences in scales used to assess SD, could reduce the significance of our findings. However, treatment-emergent SD is a frequent adverse effect that should be considered in clinical activity for the choice of the prescribed drug.