The state of Nayarit is the main oyster producer in the Mexican Pacific, this derived from artisanal crops of Crassostrea corteziensis and collecting of wild seeds. Despite its importance, there are no studies on the reproduction of this species in Boca de Camichín, Nayarit, Mexico, which is the area with the highest production (around 90%). The aim of this study was to evaluate sex ratio, condition index (CI), reproductive cycle, and recruitment size for reproduction and its relationship with environmental factors. Sixty oysters were sampled monthly at La Palicienta Lagoon for one year. The organisms were weighed and measured, then fixed with 10% formalin for histological analyses. Subsequently, the gonads were processed by histology. Sex ratio was different from 1:1, with a predominance of females. The condition index (CI) was higher from March to July. Oyster spawning was most prevalent in May, August, and October. The temperature had a positive relationship with reproduction. Recruitment size at reproduction was 57.1 mm. The results of this study could supply useful information about reproduction of the species at La Palicienta and seed collection in Boca de Camichín, Nayarit.The state of Nayarit is the main oyster producer in the Mexican Pacific, this deriving from artisanal crops. These consist of collecting wild seeds. Despite its importance, to our knowledge there are no studies on the reproduction of the oyster Crassostrea corteziensis in Boca de Camichín, Nayarit State, Mexico, which is the area with highest production (around 90%). The aim of this study was to evaluate the reproduction (sex ratio, Condition index [CI], gonadal development, reproductive cycle, and recruitment size at reproduction) and its relationship with environmental factors. Sixty oysters were sampled monthly at La Palicienta Lagoon for one year. In the laboratory, the organisms were weighed and measured and then fixed 10% formalin for histological analyses. Subsequently, the gonads were processed by histology (Hematoxylin-Eosin [H&E]). Sex ratio was different from 1:1 (p ˂0.05), with a predominance of females. The Condition index (CI) was higher from March to July. Five phases of gonadal development were observed: undifferentiated; gametogenesis; ripe; spawning, and post-spawning. In Cortez oyster spawning is most prevalent in August, May, and October. The temperature has a positive relationship with reproduction (p ˂0.05). Recruitment size at reproduction was 57.1 mm. The results of this study could contribute useful information about seed collection in Boca de Camichín, Nayarit.