This study was carried out to evaluate some domestic ('Bilecik', 'Maraş 12', 'Maraş 18', 'Şebin Şen1', 'Şen 2') and foreign walnut cultivars ('Chandler', 'Fernette', 'Fernor', 'Howard', 'Pedro', 'Serr') in the conditions of Bursa, northwest Turkey (latitude 40°11' and longitude 29°3') between 2008 and 2012. The cultivars were compared according to leafing time, bloom period of staminate and pistillate flowers, leaf fall, tree vigour and fruit characteristics. The earliest leafing was observed in the cultivar 'Maraş 12' and the latest leafing were noted in 'Fernette' and 'Fernor'. First female flowers appeared at the end of April in the 'Serr' cultivar, while the female flowers in 'Fernor' appeared at the end of May. Catkins flowered between mid-April in 'Sebin' and the end of May in 'Fernor'. Flowering of 'Sen 1' and 'Sen 2' was homogamous, the flowering of 'Bilecik' was protogynous, and other cultivars were protandrous. The earliest leaf fall was observed in 'Sen1', 'Sen 2', 'Sebin', 'Maras 12' and 'Maras 18' and the latest leaf fall was seen in 'Howard', 'Pedro' and 'Chandler'. 'Sen 1', 'Bilecik', 'Chandler' 'Maraş 12', 'Fernor', 'Pedro' exhibited higher vigour than other cultivars. All cultivars produced nuts in 2012. The fruit weight of cultivars ranged between 9.86 g ('Maraş 12') and 16.80 g ('Şen 1'). The shell thickness varied between 1.62 mm ('Sen 1') and 2.67 mm ('Howard'). The percent kernel was highest in 'Sebin' (57.22%).