Summary Much has been written about titles in scientific journal articles but little research has been carried out. We aimed to assess in two studies how factors like the length of a title and its structure might vary in different scientific fields, and whether or not these features have changed over time. Statistical analyses were made of 216,500 UK papers from science journals, and of 133,200 international oncology papers. Factors examined included title length, the use of colons in the titles, and the number of authors. All of these factors increased over time for both sets of papers, although there were some disciplinary differences in the findings. In both studies, titles with colons occurred more frequently with single than with multiple authors except when the numbers of co-authors were large. Certain features of titles can be related to different disciplines, different journals, the numbers of authors and their nationalities.