Gambusia holbrooki is the freshwater fish with the greatest distribution in Chile and the world. However, studies dealing with morphology and liver histology of fish are scarce. The liver commonly shows the sublethal effects of environmental pollutants and there should be a histomorphological description of the liver for further comparative studies. The present study aims to describe histomorphological patterns of the liver of Gambusia holbrooki. A total of 97 adult individual specimens were collected from the ecosystems in the valleys of Lluta and Azapa (Region of Arica and Parinacota), to observe patterns morphologically common in both populations. Routine histological and histochemical techniques were used for analysis. The evidence showed that the liver contains pancreatic tissue, and that tissue architecture is trabecular with greater presence of capillary sinusoids.