This study was carried out to investigate the possibilities of pak choi cultivation and to determine the suitable cultivars of pak choi under the ecological conditions of Samsun between the autumn and spring growing season in 2010-2011. In this study, three sowing dates with 15 day intervals (1st August, 15th August, 1st September) at the end of autumn period in 2010, two sowing dates (1st April, 15th April) in spring season in 2011 and three sowing dates (15th July, 1st August, 15th August) at the end of 2011 autumn season and four pak choi cultivars (Dwarf canton white, Pak choi green, Green fortune, Tai sai) were investigated. At the end of this research, it was found that pak choi vegetables could be successfully grown in autumn under the ecological conditions of Samsun. In the spring season, all of the cultivars were flowered due to the bolting. In this study, according to the year and growing season, for Dwarf canton white cultivar averagely leaf number found 14.55-18.33 units and leaf weight changed 375.06-381.65 g. For Pak choi green cultivar, leaf number found 16.0-20.33 units and leaf weight changed 252.80-327.95 g. Dwarf canton white and Pak choi green were determined as the promising cultivars. According to the years, the highest yield was determined 0.411-0.433 t ha(-1) for Dwarf canton white, and 0.313-0.345 t ha(-1) for Pak choi green cultivars. All results showed that the best suitable sowing time for the pak choi cultivation was 15th July for the autumn growing season.