A culture system was developed and evaluated as an improved diagnostic procedure for human infections of New and Old World cutaneous leishmaniasis. Needle aspirates of 55 suspect lesions from 40 human cases were made by injecting and withdrawing sterile saline from the outer margin of a lesion. Aspirates were inoculated and cultured in an insect cell culture medium, Schneider's Drosophila Medium, supplemented with 30% fetal bovine serum. Paralleled cultures in a blood-based medium, NNN, were used as a basis of comparison for sensitivity. Promastigotes were observed in 37 of 55 (67%) of the Schneider's Medium cultures on an average of 6.0 days, as compared to only 8 of 55 of the NNN cultures on an average of 11.6 days.