Aims: We performed a morphometric study of cardiac development on human embryos to complement the scarce data on human embryonic cardiac morphometry and to attempt to establish, from these, algorithms describing cardiac growth during the second month of gestation. Methods: Thirty human embryos from Carnegie stages 15–23 were included in the study. Shrinkage and compression effects from fixation and inclusion in paraffin were considered in our calculations. Results: Growth of the cardiac (whole heart) volume and volume of ventricular myocardium through the Carnegie stages were analysed by ANOVA. Linear correlation was used to describe the relationship between the ventricular myocardium and cardiac volumes. Comparisons of models were carried out through the R² statistic. The relationship volume of ventricular myocardium versus cardiac volume is expressed by the equation: cardiac volume = 0.6266 + 2.4778 volume of ventricular myocardium. The relationship cardiac volume versus crown-rump length is expressed by the equation: cardiac volume = 1.3 e^{0.126 CR length}, where e is the base of natural logarithms. Conclusion: At a clinical level, these results can contribute towards the establishment of a normogram for cardiac development, useful for the design of strategies for early diagnosis of congenital heart disease. They can also help in the study of embryogenesis, for example in the discussion of ventricular trabeculation.