The effects of replacing cocoa butter with different percentages and proportions of a mango kernel fat/palm olein (MKF/POL) blend, are reported. Samples were prepared by melting together mango kernel fat, palm olein, cocoa butter and cocoa mass and powdered sugar combinated. The samples were milled, conched, tempered, and molded to obtain three sets of seven samples as follows: one control omitting mango kernel fat and palm olein, and six samples with cocoa butter replacement of 15 and 22.5% and MKF/POL ratios of 2.3, 4.0, and 9.0. Casson viscosity, Casson yield stress, fat bloom and sensory acceptability were all measured. In fact, all samples had achieved a low Casson viscosity (ηCA) and Casson yield stress (τOCA), which indicates molding and enrobing as appropriate uses. In addition, some significant differences (p ≤ 0.05) were found among samples. Fat bloom was accelerated in the samples relative to control, but high MKF proportions tended to retard appearance of fat bloom. No differences were observed in organoleptic properties between samples and control.