The aim of this review was to assess the clinical relevance of the relative antidepressant efficacy of escitalopram and citalopram by meta-analysis. Studies in major depressive disorder (MDD) with both escitalopram and citalopram treatment arms were identified. Adult patients had to meet DSM-IV criteria for MDD. The primary outcome measure was the treatment difference in Montgomery-Asberg Depression Rating Scale (MADRS) total score at week 8 (or last assessment if <8 wk). Secondary outcome measures were response (≥ 50% improvement from baseline) and remission (MADRS ≤ 12). A search of the literature and websites found eight randomized controlled trials (RCTs) and onr naturalistic trial, with a total of 2009 patients (escitalopram, n=995; citalopram, n=1014). Escitalopram was significantly more effective than citalopram in overall treatment effect, with an estimated mean treatment difference of 1.7 points at week 8 (or last assessment if <8 wk) on the MADRS (95% CI 0.8-2.6, p=0.0002) (six RCTs used the MADRS), and in responder rate (8.3 percentage points, 95% CI 4.4-12.3) (eight RCTs) and remitter rate (17.6 percentage points, 95% CI 12.1-23.1) analyses (reported for four RCTs), corresponding to number-needed-to-treat (NNT) values of 11.9 (p<0.0001) for response and 5.7 (p<0.0001) for remission. The overall odds ratios were 1.44 (p<0.0003) for response and 1.86 (p<0.0001) for remission, in favour of escitalopram. In this meta-analysis, the statistically significant superior efficacy of escitalopram compared to citalopram was shown to be clinically relevant.