The frequency and spectrum of morphological mutations, raised in M2 after sunflower mature and immature seed treatment with ethylmethanesul phonate (EMS), were studied. Mature seeds of 3 self-pollinated lines (ZL9, ZL102, ZL169) and immature seeds of 2 lines (ZL102 and ZL169) were treated with EMS at the concentrations of 0.01%, 0.1% and 0.5% for 6 and 12 h and 0.01% and 0.1% for 6 and 12 h, respectively. We isolated and described 18 types of mutation, which were classified into the following groups: chlorophyll deficiency (6), leaf (5), stem and (4) ray floret shape and color (3). Genotypic differences were revealed for the spectrum of mutations occurring after mutagenic treatment of mature and immature seeds. Differences in mutation spectrum existed in the studied lines after treatment of mature seeds. Mutation frequency after immature seed treatment did not exceed the amount of mutations after mature seed treatment where the maximum frequency amounted to 13.2%. Chlorophyll deficiency mutations averaged a half and more of the visi ble morphological mutations.