The present application provides stabilized formulations of furin (e.g., rfurin) containing a sugar, sugar alcohol, and/or non-ionic surfactant. As compared to non-stabilized compositions, the furin formulations disclosed herein retain greater amounts of furin activity and monomeric furin content, while reducing furin aggregation when stored and/or subjected to mechanical stress. Also provided are methods for stably diluting furin (e.g., rfurin) compositions.