We compared three methods for determining the chlorophyllacontent of several aquatic macrophytes. Extraction with DMSO (dimethyl sulfoxide; 100%) yielded chlorophyllavalues which were equivalent to or slightly greater than the values for samples extracted with 90% acetone or 90% methanol. Chlorophyllaextraction with DMSO was somewhat more efficient than methanol or acetone depending on the species examined. Chlorophyllain DMSO extracts appeared to be more stable over time. The DMSO procedure is relatively quick and does not require maceration or centrifugation of the sample, and appears to be suitable for a variety of submersed aquatic macrophytes.