The estimation of socioeconomic inequalities has lately become one of the major topics in public health research, as the numerous studies are showing strong association of inequalities with health status and outcomes. The aim of this study was to provide a general overview of the individual data available for the socioeconomic inequalities estimation from a public health survey and to compare different proxies used for socioeconomic inequalities estimation. The data from the Croatian Adult Health Survey were used, which is a large representative cross-sectional study of the general Croatian population that was performed in 2003. Four variables were compared--education and occupation class, and objective and subjective socioeconomic estimation. Strong regional differences were recorded within Croatia, generally showing better socioeconomic indices in the capital, city of Zagreb. Although all of these variables were significantly associated to one another, breakdown into the gender stratified education-by-occupation groups indicated that income was unevenly distributed in these groups and that it had non-linear association with education, especially in the white-collared occupations. Although socioeconomic inequalities do show striking association with many health related indices and outcomes and should therefore be included in all types of research on human subjects, due attention is needed in research planning, data encoding and entry, as well as interpreting the results based on this data.