This study aimed to determine the effect of cocaine on the development and growth of immature and adult blowflies, in an attempt to better understand the impacts of such effects on postmortem interval (PMI) estimation. Twice the lethal dose of cocaine was injected into rabbits. The control animals were injected only with saline solution. Experimental and control rabbits were autopsied, and portions of their livers were exposed to newly eclosed larvae of Chrysomya putoria and Chrysomya albiceps. Larvae were weighed individually every 6 h, up 54 h of exposure. The larvae were then placed on an artificial diet to continue their development. Pupariation time, adult emergence and adult longevity were also analysed. The larvae of both species that fed on the cocaine-containing livers developed faster than those that fed on the livers of the control animals, leading to the conclusion that cocaine influences and stimulates larval growth. The difference in growth between the control and treated flies was best observed from 12 h of exposure onward. This finding has important implications for forensic investigations.22027-32