MgNH4PO4 center dot 6H(2)O (struvite) was crystallized from dild. phosphate(V) ions-contg. aq. solns. in a continuously operated lab. crystallizer at 298 K and pH 8.5 or 10 (residence time 900 or 3600 s), to study the effect of phosphate(V) ion concn. in a feed, molar proportions between reacting substances, pH and mean residence time of suspension in a crystallizer on the process yield, its kinetics and product quality. The best-shaped struvite crystals were produced at the phosphate(V) ion concn. 0.20% by mass, stoichiometric proportions between the reacting substances, pH 8.5 and elongated residence time 3600 s. Excess of Mg ions resulted in improving the removal of phosphate(V) ions.