Gill-net selectivity for Amblygaster (= Sardinella) sirm was studied using material collected from commercial fishing operations on the west coast of Sri Lanka during the period January-October 1985. Selectivity estimates were made by comparing fish caught by nets of different mesh sizes ranging from 2.5 cm to 3.8 cm and by using the- -fish length/girth relationship. The means of the selectivity factors estimated by the two methods were 5.53 and 5.48. These values are comparable with those obtained elsewhere for similar species. The optimal lengths and the selection factors estimated for different mesh sizes tended to increase with the mesh size. Also the large mesh size caught a greater size range of fish than the small meshes. The gill- net fisheiy effectively caught fish within the range 12.9-23.3 cm. The selection by all mesh sizes in general is towards the lower end of the selection range.