In small-group problem-based learning (PBL), students work cooperatively to solve complex, real-world problems. The problems lead the students to learn basic concepts rather than being presented as applications of concepts they have already learned. The goals are for students to learn and be able to apply the disciplinary content, develop critical thinking abilities, and acquire skills of life-long learning, communication, and team building. PBL has been widely used in recent years in medical and related areas of professional education. In those settings each small group typically has its own faculty facilitator. PBL can be successfully adapted for teaching undergraduate and graduate basic science students, in part by having multiple groups meet in one room with a roving facilitator. This report describes a two-semester PBL sequence in organ-systems physiology. To keep the interest of a diverse group of seniors and graduate students, several types of problems were used: clinical, laboratory research-based, real-life scenarios, and published research articles. The majority of students have responded enthusiastically.