Objectives The aims of the study were to compare the results of systolic blood pressure (SBP) measurements at the radial and coccygeal artery by Doppler ultrasonography and to assess the impact of gender, age, body weight, body condition score (BCS) and stress score on disagreements. Methods Eighty cats were included in this prospective, block randomised crossover trial. Blood pressure measurements were performed at home, during hospitalisation or in a local animal shelter by a single trained observer according to the latest ISFM consensus guidelines. Statistical analysis included Spearman's correlation and ANOVA. Results Measurement or site order had no effect on blood pressure measurements ( P = 0.157, P = 0.965). Correlation of radial and coccygeal SBP was moderate (rsp = 0.519, P <0.001) and measurements at the tail were by mean 18.7 ± 37 mmHg higher. The differences between the measuring sites were neither correlated with age (rsp = 0.044, P = 0.710) nor with body weight (rsp = 0.122, P = 0.337). A significant effect of BCS ( P = 0.016), but not gender ( P = 0.246) or stress score ( P = 0.424) was identified. Of the 25 cats with a coccygeal SBP ⩾170 mmHg, 14 (56%) were categorised as mildly hypertensive or normotensive when measurements were performed at the forelimb. Conclusions and relevance Choice of the measuring site, coccygeal vs radial artery, has a significant impact on Doppler ultrasonographic SBP results. In many cats, these discrepancies are huge and would certainly affect treatment decisions. Possible explanations include cone-shaped tails, especially in obese cats, leading to distal gapping or slippage of cylindrical cuffs and peripheral pulse pressure amplification. Further studies are urgently needed to clarify whether the discordances are artefacts or have a pathological background.