A brief review of the characteristics of storm and combined sewer flows is given, followed by a general discussion of the purposes for and requirements of a sampling program. The desirable characteristics of automatic sampling equipment are set forth, and problem areas are outlined. A discussion of various commercially available and custom designed automatic samplers is given with brief descriptions and characterizations of some units presented along with comments on their suitability for a storm or combined sewer application or both. A review of some field experience with automatic sampling equipment is given covering problems encountered and lessons learned. A technical assessment of the state of the art in automatic sampler technology is presented, and design guides for development of a new, improved automatic sampler for use in storm and combined sewers are given.