The effect of some factors, namely BA concentration (5 and 10 mg/l), sucrose concentration (8, 10, 12, 13, 14 and 15%) and presence of active charcoal in medium (0 and 5 g/l) on microtuber formation of six potato genotypes, four tetraploid, viz. Diamant, Picasso, Santa and Forella and two dihapliod, namely 805 and 808, was studied in two experiments. Potato genotypes responded differently to such factors, where Forella cv. showed the best performance regarding microtuber number per jar, average weight of microtuber, and microtuber yield per jar. Increasing sucrose concentration up to 12% and adding active charcoal at concentration of 5 g/l in medium having 10 mg/l BA caused a remarkable increase in microtuberization parameters in all cultivars. On the other hand, increasing sucrose concentration or adding 5 g/l active charcoal to MS medium having 5 mg BA /l promoted microtuber formation in some cultivars, and inhibited this process in others.