Ketosis is a common disease in dairy cattle, especially in the days after calving, and is often undiagnosed. The objective of this study was to compare the standing behaviour of dairy cows with and without ketosis during the days around calving to determine if changes in this behaviour could be useful in the early identification of sick cows. Serum beta-hydroxybutyrate (BHBA) was measured in 370 cows on three commercial dairy farms, twice weekly from 2 to 21 d after calving. Standing behaviour was measured from 7 d before calving to 21 d after calving using data loggers. Retrospectively, 19 cows with subclinical ketosis (BHBA ≥1.2 and ≤ 2.9 mmol/L) and 20 cows with clinical ketosis (BHBA >2.9 mmol/L) were matched by farm with 39 non-ketotic cows (BHBA <1.2 mmol/L). Five periods were defined for the statistical analyses: wk -1 (d -7 to d -1), d 0 (day of calving), wk +1 (d 1 to d 7), wk +2 (d 8 to d 14) and wk +3 (d 15 to d 21). The first signs of both subclinical and clinical ketosis occurred 4.5 ± 2.0 d after calving. The standing behaviour of cows diagnosed with subclinical ketosis was not different than non-ketotic cows during any period. Total daily standing time was longer for clinically ketotic cows relative to non-ketotic cows during wk +1 (14.4 ± 0.8 vs. 12.2 ± 0.7 h/d) and d 0 (17.6 ± 1.0 vs. 13.4 ± 0.7 h/d) but was not different during the other periods. Clinically ketotic cows exhibited fewer standing bouts compared to non-ketotic cows on d 0 only (12.8 ± 2.2 vs. 18.1 ± 1.6 bouts/d). Average standing bout duration was also longer for clinically ketotic cows on d 0 compared to non-ketotic cows (64.9 vs. 40.4 min/bout) but was not different during the other periods. These results suggest that differences in standing behaviour before calving may be useful for the early detection of clinical ketosis in dairy cows.