Data from 211 adult students (ages 20 to 75) at the Open University, The Netherlands, were used to construct and test an instrument to measure learning styles and regulation processes. Test development was guided by a three-tiered model of self-regulation encompassing: (1) cognitive learning processes (deep, surface, elaborative); (2) regulation processes (planning, monitoring, self-testing, etc.); and (3) conceptual processes (metacognitive knowledge and beliefs about learning). A pilot interview study with 24 students (phenomenographic method) yielded three styles: self-regulation, external regulation, or lack of regulation. In the main study, 211 students (out of 700 contacted) completed 50 regulation and 50 learning approach items. Principal components analysis identified items most indicative of self-regulation, external regulation, or lack of regulation (these items are included). Similar analyses yielded scales for deep, surface, and elaborative learning style (items not presented). Higher education background was associated with lower scores for external regulation and lack of regulation. Students just beginning at the Open University reported greater lack of regulation and elaborative learning style. These scales are part of a larger projected Inventory of Learning Styles, Conceptions, and Orientations. (LPG)