This systematic review aimed to determine frequency, trend, and lethality of common methods of suicide in Iran through literature in relevant studies by meta-analysis. We searched MeSH heading suicide and/or keyword combinations in published articles in English major databases (PubMed, Scopus, and ISI) and Persian databases (Magiran, Medlib, SID, and Iran Medex). Based on the inclusion and exclusion criteria, we enrolled 47 relevant studies for the final analysis. The data were analyzed based on a random-effects model using Stata11.2. We found that hanging had the highest lethality among suicide methods; so that hanging with 14.9% (95% CI: 12.6, 17.3) and followed by self-immolation with 11.8% (95% CI: 10.2, 13.3) lethality were the common lethal methods. Results showed a decreasing trend in the rate of using lethal methods (β=−0.02, 95% CI: −0.005–0.05), (p=0.017) across the study period. Our results approve this assumption that the rate of using lethal methods for suicide is decreasing in recent years in Iran, perhaps opposite to non-violent methods. This is an important finding that investigators should be assessed it in forward studies to clarify the possible causes.