In the paper, the soluble sugar composition and activities of enzymes metabolizing sucrose: invertase (β-fructosidase, EC 22.214.171.124), sucrose synthase (SS; EC 126.96.36.199) and sucrose-phosphate synthase (SPS; EC 188.8.131.52) were investigated during fruit development of two pear species: Pyrus bretschneideri Rehd. cv. ‘Yali’ and P. pyrifolia Nakai cv. ‘Aikansui’, characterized as low and high sucrose types, respectively. It was found that, at the end of fruit development of ‘Aikansui’, the level of sucrose was five times higher than in ‘Yali’ in the same period. It was coincident with the significantly higher activities of SS (synthesis) and SPS and lower activities of invertase (vacuolar and cell wall-bound acid invertase and neutral invertase). The high correlation was found between sucrose level and SS (synthesis) and SPS activities in ‘Aikansui’ pears.