abstract:In this study, we examined the technical efficiency of black tiger prawn aquafarms before and after the shrimp diseases outbreak (1986-1999). Fourteen years balanced data of 31 aquafarms from six regions around Taiwan were assessed using stochastic production frontier panel. Two alternative functional forms (Cobb-Douglas and Translog production functions) were applied. Results show that the Cobb-Douglas form is an adequate representation of Taiwanese black tiger prawn data, given the specifications of the Translog model. The input elasticities of feed, labor and utility were 0.30, 0.07 and -0.03, respectively. It implied production technology in Taiwan is decreasing return to scale. Stocking density, culture type, survival rate and the dummies of diseases were significant factors affecting aquafarmer’s technical inefficiency. The technical efficiency was 0.79, before the shrimp disease outbreak in 1987 which was higher than the mean technical efficiency (0.46) of all aquafarmers over the 14-year period. After the shrimp disease outbreak, the av erage technical ef f iciency was 0.41.