Abstract The objective was to establish the breed-specific echocardiographic reference intervals for end-diastolic volume and end-systolic volume of the left ventricle obtained through biplane Simpson’s method of discs (SMOD) in the show jumping and Polo Argentine Saddle horse. The determination of central 90% reference limits was calculated, and its confidence intervals and reference intervals were reported with 90% confidentiality. A comparison was made between the cardiac SMOD-derived volumes and Teichholz-derived volumes. 39 horses were selected to create the reference intervals and the EDVI SMOD-derived was 1.32ml/kg, RI 1.26–1.37 and ESVI SMOD-derived was 0.47ml/kg, RI 0.43–0.50. There was a clinically relevant difference between EDVI SMOD-derived and EDVI Teichholz-derived volumes, p < 0.001, d = 1.14. The ESVI SMOD-derived volumes were clinically relevant and different from Teichholz-derived volumes, Z = -2.03, p < 0.05, r = 0.33. The EDVI in males was statistically equal to EDVI in females, p = 0.72, r = 0.39. The ESVI in males was statistically equal to ESVI in females, p = 0.12, r = 0.33. In conclusion, it is feasible, as in humans and dogs, to obtain SMOD-derived ventricular volumes in horses, and can be useful for clinical and research purposes.