According to the Journal Citation Report from the Institute for Scientific Information (ISI), the last year's (2003) impact factor (IF) of the Croatian Medical Journal (CMJ) was 0.943. To determine the factors that contributed to this significant increase in the IF, we analyzed the structure of citations to CMJ in the ISI's publications, Science Citation Index (SCI), and Social Science Citation Index (SSCI). Thematic issues generally acquired more citations than regular issues. Furthermore, citation number varied for different article types. The citations to the original scientific articles corresponded to the average number of citations for the current IF value, whereas reviews and especially case reports were cited less frequently, and negatively contributed to the IF of the journal. Only half of all articles published in two previous years were cited in 2003. The majority of these articles were cited once or twice, whereas only 15 articles received more than three citations. Journal self-citations are still an important contributor to the CMJ's IF (39.6%). Their proportion may decrease in time, by further improving the visibility of the journal, and thus acquiring greater number of independent citations. In future, we can expect year-to-year variations in the journals IF. This trend may be positive on a long-term basis, but expectation of a value significantly higher than 1 is unrealistic. CMJ is small general medical journal whose quality-oriented editorial policy may in the long-term result in the increase in the IF.