In modern pear cultivation, clonal quince and pear rootstocks are preferred because they are easy to maintain and harvest. Also, they form dwarf plants and improve fruit quality compared to pear seedling rootstocks. However, graft incompatibility can be involved between different species or genera. The aim of the study was to determine the graft compatibility of the ‘Deveci’ and ‘Williams’ pear cultivars with different pear and quince rootstocks by carbohydrate analysis. Carbohydrate accumulation in the graft union was also observed with iodized potassium iodide (KI) staining. In terms of rootstocks, there were no differences in starch and carbohydrate content, but statistically differences were found in sugar contents. Significant differences were also found between cultivars and graft union in terms of the examined traits. Sugar content was highest in OHxF 333 and lowest in seedling rootstocks. There were no statistical differences in the starch content between the graft unions of the ‘Deveci’ cultivar, while starch accumulation was higher above the graft union than below and graft union in the ‘Williams’ cultivar grafted on the quince rootstock. In the study, it was determined that there were higher carbohydrate accumulation in the scion and graft union than below the graft union in ‘Williams’ grafted quince rootstocks, which was also confirmed by staining with KI. As a result of the study, it was concluded that carbohydrate accumulation analysis can be used to determine the graft compatibility of the pear cultivars with the different quince and pear rootstocks.