Objective: To assess the relative antidepressant efficacy of escitalopram and comparator antidepressants. Research design and methods: A meta-analysis was performed using studies in major depressive disorder (MDD) comparing escitalopram with active controls, including selective serotonin reuptake inhibitors [SSRIs] (citalopram, fluoxetine, paroxetine, sertraline) and serotonin/noradrenaline reuptake inhibitors [SNRIs] (venlafaxine, duloxetine). Adult patients had to meet DSM-IV criteria for MDD. Main outcome measures: The primary outcome measure was the treatment difference in Montgomery-Asberg Depression Rating Scale (MADRS) total score at week 8. Secondary outcome measures were response and remission (MADRS total score <= 12) rates. Results: Individual patient data (N = 4549) from 16 randomized controlled trials were included in the analyses (escitalopram n = 2272, SSRIs n = 1750, SNRIs n = 527). Escitalopram was significantly more effective than comparators in overall treatment effect, with an estimated mean treatment difference of 1.1 points on the MADRS (p<0.0001), and in responder (63.7 vs. 58.3%, p<0.0001) and remitter (53.1 vs. 49.4%, p<0.0059) analyses. Escitalopram was significantly superior to SSRIs, with an estimated difference in response of 62.1 vs. 58.4% and remission of 51.6 vs. 49.0%. In comparison to SNRIs, the estimated difference in response was 68.3 vs. 59.0% (p < 0.0007) and for remission the difference was 57.8 vs. 50.5% (p = 0.0088). These results were similar for severely depressed patients (baseline MADRS >= 30). Sensitivity analyses were performed with data from articles reporting Hamilton Rating Scale for Depression (HAMD) scores. The 8-week withdrawal rate due to adverse events was 5.4% for escitalopram and 7.9% for the comparators (p<0.01). This difference was accounted for by statistically significant higher attrition rates in the SNRI comparisons. This work may be limited by the clinical methodology underlying meta-analytic studies, in particular, the exclusion of trials that fail to meet predetermined criteria for inclusion. Conclusions: In this meta-analysis, superior efficacy of escitalopram compared to SSRIs and SNRIs was confirmed, although the superiority over SSRIs was largely explained by differences between escitalopram and citalopram.