Purpose:Assessment of zirconia and  stainless steel crowns in restoration of  primary molars(clinical and radiograph) Methods: One hundred and twenty   randomly selected Egyptian children received bilateral crowns to  first or second primary molars, one side was restored by stainless steel crowns (group A) and the other side was restored by zirconia crowns (group B)  Results: There was significant increase in score of gingival index  for both SSC and zirconia crowns after 1 week and after 6 months but increase in score was more in SSC than zirconia crowns. There was significant increase in score of debris index for SSC after 1 week and after 6 months and there was insignificant increase in score for zirconia crowns after 1 week and after 6 months. There was no statistically significant difference in alveolar bone height in both groups (zirconia and SSCs) Immediately after cementation and after 6 monthsConclusions: Zirconia crowns presented to be an excellent choice for primary posterior teeth full coverage restorations. Zirconia crowns performed better than SSCs in the aspect of esthetic, gingival response and prevention of plaque adhesion.