An experiment was conducted at Siwa Oasis Research Station, Matrooh Governorate, Desert Research Center in two consecutive winter seasons, 2012 and 2013 to determine the effects of four planting dates (1^st of Jan., mid of Jan., 1^st of Feb. and mid. of  Feb.) and three potato seed tuber sources of spunta cultivar (imported certified seed tubers, local seed tubers and recently harvested seed tubers which treated with GA₃ ) on growth and yield under Siwa conditions.  The results showed that planting on mid. of Jan.  (date2) and 1^st of Feb. (date 3)  , generally, produced the highest growth and  total yield and its components values. On the other hand, 1^st of Jan. (date 1) and mid. of Feb. (date 4) gave the lowest values. Base temperature calculation for potato  revealed that it was 5.99 ^oC and accumulated heat units above base temperature were 191.56 ± 12.4 degree-days during emergence period. The results showed , also, that Imported seed tubers (source 1) showed superiority in most studied characters of vegetative growth and yield parameters  , followed by local seed tubers (source 2) as compared with  recently harvested seed tubers (source 3). Generally, satisfactory characters were obtained when imported seed tubers were planted on mid. of Jan. (date 2) or first of Feb. (date 3) in both two seasons. Highly significant positive correlations were found between yield/fe d. and either yield/plant or average tuber weight. On the contrary, significant negative correlation was found between yield/fed. and number of tuber /plant.  Correlation and regression revealed ,also, that increasing number of plant leaves led to increasing of plant fresh weight and average of tuber weight. While increasing number of plant shoots led to increasing number of tubers and decreasing tuber weight.