-A 6 x 6 complete diallel mating design was used to study the inheritance of different plant traits in upland cotton (Gossypium hirsutum L.). Six genotypes viz., BJA-592, ACALA-SJ-4, 4-F, CP-15/2, CIM-497 and PB-899 were included in diallel crosses. Results revealed that over-dominance type of gene action was controlling the inheritance of monopodial and sympodial branches plant height number of bolls and boll weight. The line CP-15/2 possessed maximum dominant genes for monopodial branches, plant height and boll weight, BJA-592 for sympodial branches and ACALA-SJ-4 has maximum dominant genes for bolls per plant. However the cultivar CIM-497 carried maximum recessive genes for monopodial branches and plant height, PB-899 for bolls per plant and sympodial branches while ACALA-SJ-4 has maximum recessive genes for boll weight.