Studies have been continued on the synthesis of glycolipids by the NIL 2 line of hamster cells. Several clones were isolated from this line. These clones vary in morphology, saturation density, and glycolipid composition. Contrary to expectation there was no correlation between saturation density and complexity of the glycolipid pattern. In fact, the clone with the highest saturation density was the only one to show the complete set of glycolipids found previously in NIL 2 cells. All untransformed NIL clones show an increase in the level of "higher" (more than two saccharides/ceramide) glycolipids as the cells approach confluence. In the line containing all three "higher" neutral glycolipids, all three increased as cells approached saturation density. In the line containing only hematoside, this compound increased at confluence. Cells transformed by hamster sarcoma virus or polyoma virus showed no density-dependent glycolipid synthesis.