SUMMARY The loss of farmland in four counties of south‐central Ontario was examined for the 1951–71 period, with the use of township census data. The study has indicated the need to be cautious regarding the accuracy of official statistics. Regression analysis of the census data revealed that the best predictor of farmland loss was the extent of part‐time farming. Since 1971, the role of part‐time farming has changed greatly. The percentage of part‐time farmers is increasing steadily because off‐farm income is vital to the maintenance of the economic viability of farming today. In contrast to the 1950s and 1960s, the part‐time farmer now is often coming into full‐time farming rather than phasing out. The results of this analysis present further evidence of the complexity of the loss‐of‐farmland problem and the variability of the findings that emerge from studies conducted for different periods