A number of cognitive skills relevant to design have been identified. Formal methods for evaluating these skills in engineering students are needed. Towards that goal we are developing a battery of standardized tests for the most critical of these skills. These tests are based on research in design thinking, human problem solving, cognitive psychology and psychometrics. Tests for Divergent Thinking, Visual Thinking, Spatial Reasoning, Qualitative Reasoning and Problem Formulation are in various stages of development. This paper describes the procedure and rationale for test development. Tt involves characterization of design skills in terms of measurable indicators; devising skill measurement instruments (problems, metrics, scales); conducting trials to collect data and evaluation of tests for criterion and construct validity. Beta trials are in progress involving undergraduate and graduate students at multiple universities and engineers in industry. Possible applications of these tests include evaluating students in design classes, forming of balanced design teams that posses skills necessary for a given project and evaluating the effectiveness of design courses and curricula.