The fluid catalytic cracking (FCC) behavior of compound types present in the >650 degrees F resid from Lagomedio crude was investigated. Distillation and liquid chromatography were employed for separation of selected compound type fractions from the resid; the resulting fractions were then cracked using a bench-scale FCC unit. The FCC behavior for each compound type was defined in terms of the resulting product distribution (yields of gas, gasoline, etc.); sulfur, nitrogen, nickel, and vanadium partitioning; and in selected cases, gasoline composition. Results obtained from Lagomedio fractions were compared to those obtained from earlier FCC studies of compound types from Wilmington, CA, Maya (Mexican), and Brass River (Nigerian) >650 degrees F resids, An equation is presented for prediction of gasoline yield for feedstocks derived from Lagomedio as well as other crudes. Gasoline yield (wt % of feed) is calculated from these feedstock parameters: the atomic ratio of hydrogen divided by carbon plus sulfur (H/(C + S)), the fraction of the feed volatilized at the cracking temperature f(c)T, effective metal content (M-eff = Ni + V/4) expressed in mu equiv/g, basic nitrogen (N-B, wt %) and amide-type nitrogen (N-Am, wt %). The relation is G = 10.25[H/(C + S) + log(f(c)T)] - 1.5M(eff) - 29(N-B + N-Am) + 30.2. Calculated and experimental gasoline yields typically agreed within 1.5 wt %, which is the pooled standard deviation for the experimental data. An infrared spectrophotometric method is provided for determination of N-Am; the other parameters are measured using standard methods or previously published procedures.