Dating of prehistoric rock paintings or pictographs has traditionally relied on indirect evidence. This includes inferences based on the archaeological context, such as superpositions of pictorial styles and the depiction of images that constrain their ages, as well as dating of deposits that either cover the art in situ or contain separated fragments of the painted surface. Migration of ions between the bulk rock and the natural coatings that form on a newly exposed surface has also been exploited to date petroglyphs or rock carvings in desert regions. Until recently, however, direct dating of pictographs by radiocarbon dating has not been possible, mainly because of the problem of separating inorganic carbon from the organic material in the pigments. This article reports on a new technique which allows this separation to be effected by using a low-temperature, low-pressure oxygen plasma to oxidize selectively the organic component; this may then be analyzed using standard carbon-14 methods. This technique was applied to a portion of a pictograph from the Lower Pecos region of southwest Texas. The date obtained, 3, 865±100 year BP is consistent with that expected on the basis of archaeological inference. As organic carbon is a ubiquitous component of pictograph paints, this technique should be applicable to rock paintings throughout the world. -- AATA