Abstract: Fertility rate is an important health issue in the world which has been influenced by different factors and attracts the researchers’ attention. In this study influences of climate factors on fertility rate were investigated. In this analytical correlational study, relationship between climate factors and fertility rate among the healthy and infertile women who referred to Imam educational hospital in Sari, North of Iran, during 2006-2012 was investigated. Results indicated that climatic factors such as: Temperature (r = -0.324, p = 0.005), air pressure (r = 0.2495, p = 0.031) and rainfall (r = 0.415, sig<0.001) had relationship with healthy women’ fertility rate, although, this relationship was not found in infertile women. Also, fecundity peak of infertile women similar to the fecundity peak of healthy women was during autumn. Considering influences of climate factors on fertility rate could be helpful for developing child birth strategies.