The available and experimentally obtained data on phase matching in AgGaS2 crystals are analyzed. Model and experimental results for OPO and TWO of type I are presented. The radiation spectrum of nanosecond OPO overlaps the 2.65-5.29 μm range at a long-term operation stability and in the absence of saturation effect in the output power. Best-fit Sellmeier equations for AgGaS2 are identified among the available ones.