An extensive study (276 samples) was conducted in 1960 to correlate cranberry (Vaccinium macrocarpon, Ait.) bog soil pH and productivity (Chandler, F. B. and Demoranville, I. E. 1961. Cranberries 26(3):9-10). At that time, soil pH averaged 4.37 and excellent productivity was represented by a yield greater than 10 mT/ha. Thirty years later, when more than 28 mT/ha is considered good yield, soil samples will be collected from these same sites and evaluated for pH by the methods used previously. Production records for the pact three years will be obtained and the average value for each location used to construct a regression of bog yield vs soil pH. Information presented will include: 1. productivity vs soil pH in 1960 and 1990; 2. change in soil pH after 30 years?; 3. possible reasons for changes-if any (grower interviews); 4. implications for the future.