The poppy is a plant that can be planted in the autumn and spring seasons. The purpose of the research was to investigate the effects of autumn and spring sowing on capsule yield, seed yield, yield components, oil content and morphine content of fifteen poppy cultivars that have been recently registered under Isparta conditions. The experiment was arranged according to the randomized complete-block design with three replicates during the years of 2012/13 and 2013/14. The results of the research showed that the differences among capsule yields, seed yields, yield components and morphine contents of the cultivars were statistically significant in both sowing times and years. The highest and the lowest values of plant height, capsules number, capsule width, capsule length, 1000 seed weight and oil yield of the poppy cultivars varied according to the cultivars, the sowing times and the years. The capsule yield and seed yield of the poppy cultivars in the autumn sowing varied between 416.7-1043.3 kg ha(-1) and 523.5-1276.3 kg ha(-1) in the first year, between 465.3-1375.6 kg ha(-1) and 596.7-1520.4 kg ha(-1) in the second year, respectively. In the spring sowing, the capsule yield and seed yield of the poppy cultivars varied between 204.3-455.7 kg ha(-1) and 286.0-573.0 kg ha(-1) in the first year, between 497.2-830.7 kg ha(-1) and 614.3-962.7 kg ha(-1) in the second year, respectively. The highest oil content was determined in the Zaferyolu cultivar in both years and sowing times. The morphine content of the poppy cultivars varied between 0.47-1.00% in the autumn sowing and between 0.45-0.97% in the spring sowing, respectively. The higher values in the autumn sowing were obtained than the spring sowing in all of the characteristics investigated in both years, except for the oil content. Considering the present results, TMO-3, Ofis-4, Ofis-8, Tinaztepe and Zaferyolu cultivars were advised in the autumn sowing and the TMO-1, Ofis-8 and Afyon-95 cultivars in the spring sowing because of their higher capsule, seed and oil yields. In point of the morphine contents, the TMO-3, TMO-T, Ofis-3, Ofis-8 and Bolvadin-95 cultivars were advised.