PURPOSE: To provide a process for the crystallization of aspartame by neutralizing an aqueous solution of aspartame having a specific acidic pH value with a base, homogenizing the product by agitation, stopping the mechanical agitation when the crystallization becomes visible and depositing large crystal of the subject compound having low filtration resistance without cooling the system for a long period.

CONSTITUTION: Aspartame is crystallized from an aqueous solution of aspartame having a pH of <3 by the neutralization with a base and he homogenization by forced convention flow. Aspartame crystal having relatively large crystal size and low filtration resistance can be produced dispensing with a prolonged cooling step by neutralizing an aqueous solution of aspartame having a pH of <3 and an aspartame concentration of 1.5-20 wt.% with an aqueous solution of sodium hydroxide, etc., under vigorous agitation at 5-80°C to effect the neutralization and homogenization of the aspartame solution under a condition to get a homogeneous aqueous solution and a pH of >3 after neutralization and, after the continuance of the homogenization for ≤10 sec, depositing the crystal for 2 min to 2 hr without performing the mechanical agitation of the solution at or after the time when the crystallization reaches a visually sensible state.