Abstract The aim of the present study was to describe the stages of ovarian development in the eubrachyuran crab Goyazana castelnaui through macroscopic and microscopic analyses and estimate size at physiological sexual maturity. Four ovarian development stages have been defined in the 60 G. castelnaui females that were analysed from the São Pedro River in the municipality of Ouricurí (semiarid region of the state of Pernambuco, Brazil), between November 2011 and October 2012. The crabs were collected and sent to the Semiarid Crustaceans Laboratory of the Cariri Regional University. Each specimen was measured. Ovaries were classified using a visual scale, removed with needle-nose pincers, fixed, and processed for microscopic analysis. Gonad stages were determined macroscopically using a staining process and were confirmed by histological analysis (initial, intermediate, mature and spawned). Size at physiological sexual maturity was determined to be 37.67 mm carapace width for females of this species.