A guarescent derivative ofcerebroside sulf;xte, pyrene-dodecanoyi sphingasyfgaract~sylsutfate (PIZ-CS) was incorporated into the envelope of vesf cular stomatitis virus (VEX). When the P12XX&mtaining virus was incubated for 24 h with skin fibroblasts, up to 40% of the sulfatide was located in the cells -a value at least 10 fold greater than that observed using sulfatide suspensions without virus. In a similar experiment, in which the 24 h "pulse' was followed by a 48 h 'chase', about E--20% of the virus-associated fluarescence was recovered in the skin Frbrablasts. Of the latter, about one-third was present as desulfated degradation products of P12-CS. The high uptake and degradation of the virusassociated sulfatide by intact skin fibroblasts suggested that on~d~psd viruses could be used for introducing other lipids into cells. This could be utiked for studying lipid catabolism and diagnosing lipid storage disarders in intact living cells.Cerebroside sulfa% Fhmreseent sulfatide; Pyrene suEtide; R~p~or~~t~ endocytosis; Sulfatide uptake; ~n~a~~~~~~ sulfatide metaboliiq Vesicular stoma&is virus