Phylogenetic relationships between derived subfamilies of Apocynaceae s.l. as well as within the subfamily Secamonoideae have been inferred using maximum parsimony and Bayesian analyses. Characters are provided by four chloroplast sequences: matK, trnT-L and trnL-F spacers, and trnL intron. Phylogenies from both analyses show a sister group relationship between a clade of derived Apocynoideae included in the subtribe Baisseinae (tribe Apocyneae) and another clade including representatives from the Secamonoideae and Asclepiadoideae. Within the Secamonoideae, two genera, Pervillaea Decne. and Secamonopsis Jum., are strongly supported as monophyletic, whereas the monophyly of the largest genus, Secamone R. Br., remains uncertain. Palynological and morphological characters are discussed for the Malagasy Secamone in relation to one of the most parsimonious molecular trees.