This SAE Recommended Practice defines a procedure, which will aid in assessing the contaminant sensitivity of hydraulic valves. The approach taken defines a test procedure with flexibility for testing valves in a wide range of contamination levels. The user of this procedure must establish the contamination levels for testing. Three levels are suggested which should cover the range for most valve applications. This procedure does not establish the contaminant sensitivity requirements for any valve. The user of this procedure needs to be aware of the system contamination level that the valve will operate in and select test contamination levels significantly higher than the operating level to assess the suitability of the valve. The test procedure permits a valve to be tested without disassembly and therefore permits protection of proprietary design information.