The number of signing authors in Revista Clínica Española. Revista Española de Fisiología and Revista Española de Oncología have been analyzed from their first to the last received issue. The results obtained show an increasing number of authors in all journals specially during the 70s. The results also point out a relative decrease in the number of authors in basic sciences in relation to clinical publications. The increase in the number of authors in The Revista Española de Oncología has started somewhat later than the others. The environmental and professional stress as well as the interrelations between different hospital members have been suggested, amongst others, as the possible cause of these events.