OBJECTIVES When the WHO launched the Expanded Programme on Immunisation (EPI) in 1974, <5% of the world’s children were vaccinated against polio, measles, diphtheria, tetanus, pertussis and tuberculosis. Nowadays coverage rates are increasing and more vaccines have been added to the programme. This project aims to identify factors associated with successful programmes based on EPI coverage. METHODS The relationship between multiple socio-demographic and economic factors and EPI coverage (primarily obtained from the WHO and World Bank) was investigated using simple linear regression, Principal Component Analysis (PCA) to identify explanatory variables, and finally multiple linear regression analysis. 132 countries with data on self-funded healthcare programmes were included in the analysis.  These were ranked according to Gross National Income (GNI) per capita and lower (L), lower-middle (LM), upper-middle (UM) and upper (U) quartiles were identified. RESULTS Income (GNI/capita) was not significantly associated with achieving high EPI coverage rates. Within the income groups the factors trending with improved EPI coverage included: 5-yr mortality and corruption index in L, sanitary facilities in LM, 5-yr mortality, sanitary facilities, birth-rate and life-expectancy in UM.  In U all countries achieved >90% coverage.  CONCLUSIONS Identifying simple predictive variables of successful vaccination programmes is complex because of multicollinearity. However, by exploring within homogeneous income groups, it was possible to identify underlying factors related to vaccination programme success. As the core EPI vaccines were introduced 40yrs ago one would expect introduction to have been fully implemented thus reducing the likelihood of a relationship between country income and coverage today, however it could have been expected some time ago. To further explore the relationship between country income and vaccination programme success, one could expand the analysis to include the newer vaccines as soon as coverage information is available for a majority of the countries.