Metal dialkyldithiophosphates are suitable for selective detection with a flame photometric detector operated in either the S2 or HPO emission mode. Comparison of dta for packed and capillary columns shows that the sensitivity in the HPO mode is only slightly greater than, and in the S2 mode comparable with, that in the flame ionization deterctor. In addition, it is notable that hte sensitivity to the chelates in the HPO mode is inferior to that for simple organophosphorus compounds by an order of magnitude. Background permeation of CS2 leads to some improvement in detection limits for nickel dithiophosphate. Baseline resolution of palladium and platinum derivatives is readily achieved on wall-coated open-tubular columns.