An effective chromosome doubling protocol was developed in African marigold (Tagetes erecta L.) Cv. Local Orange. The different concentrations of colchicine (50, 75 and 100 mg/L), oryzalin (50, 75 and 100mg/L) and the combination of the two above mentioned anti-mitotic agents (50 and 75mg/L) was used on anther derived haploid nodal segments/explant of marigold for different durations (18 and 38 hours for each concentration). Based on the results obtained, highest percent diploidized shoots (75.40% and 64.80%) was found in experiments where nodal segments were treated with oryzalin @ 50mg/L for 38 hrs and colchicine @ 100mg/L for 38 hours respectively. In case of combination highest percent diploidized shoots was 54.4% which was found with colchicine plus oryzalin @ 75mg/L of each for 38 hours. However, the highest survival of shoots was found in control (no chemical treatment) in all the three categories. Increasing the concentrations of applied antimitotic agents led to the significant reduction in the survival rate of nodal explants, especially when the explants were exposed for longer durations.