To analyse the frequency of the cause of death in the mortality statistical Bulletin, a study of a representative sample of the 1988 mortality statistical Bulletin (n = 595) of Asturias was conducted. The mean and the mode of the number of causes and also the complexity and density according to age and sex was analyzed. The mode of the total number of causes in Bulletins for both sexes was 3, and the mean was 3.14. The three lines (complexity) were occupied in almost 50% of the Bulletins analysed. With respect to the density of lines, line IIb (initial cause) was the one occupied most of the time (10.7%), this showing more than one diagnosis when it was the last line used. Both values, complexity and density of the last line used, increased proportionally with the age at death. This analysis was also carried out excluding the causes coded as Cardiac and Respiratory Arrest (ICD-9 = 427.5; 799.1). With these results, it was possible to confirm the usefulness of the coding of multiple causes of death in Asturias, Spain.