Ten dairy farms known to have had cattle with Johne's disease were evaluated for the presence of M. paratuberculosis in environmental samples of soil, floor scrapings, bedding and barnyard organic material. Of approximately 50 samples obtained from each farm, 15-20 were from designated locations within the barn and 20-30 from the fields, creek banks, pastures and exercise lots outside the barns. Five out of the eleven farms with a recent history of Johne's disease had positive cultures but generally with low colony counts. The highest frequency of positive cultures occurred on farms with the largest number of heavily infected cattle. The risk of environmental contamination was low on most farms with known infected cattle even if culture positive animals were present. Of the 672 total samples cultured, 3.0% yielded M. paratuberculosis. The most frequent positive isolation sites were from pastures and exercise lots. The maternity stall sample on the most heavily infected farm had 17-40 colonies per tube. Separation of young cattle from adult cattle potentially shedding the bacteria in the environment remains an important management recommendation.