This paper concentrates on modeling probabilistic events with fuzzy probability measures in the object-oriented databases. Instead of crisp probability measures or interval probability measures of objects and classes, fuzzy sets are used to represent imprecise probability measures. A probabilistic object-oriented database model with fuzzy probability measures is introduced, which incorporates fuzzy probability degrees to handle imprecision and uncertainty. Based on the proposed probabilistic object-oriented database model, several major semantic relationships of probabilistic objects and probabilistic classes with fuzzy probability measures are investigated in the paper. Finally we define some algebraic operations for probabilistic objects and probabilistic classes with fuzzy probability measures.