OBJECTIVE: To investigate the prevalence and characteristics of the practice of explicitly giving authors equal credit in publications of major journals of critical care medicine. METHODS: Manual searches were conducted to indentify original research articles with equally credited authors published between January 1, 2001 and December 31, 2010 in four major journals of critical care medicine (American Journal of Respiratory and Critical Care Medicine, Critical Care Medicine, Intensive Care Medicine, and Critical Care). RESULTS: The practice of explicitly giving authors equal credit was found in all four journals. Articles with equally credited authors formed a greater proportion of the total number of articles published in each journal in 2010 vs. in 2000 (American Journal of Respiratory and Critical Care Medicine: 19.9% vs. 0%; Critical Care Medicine: 10.6% vs. 1.3%; Intensive Care Medicine: 5.3% vs. 0%; and Critical Care: 11.7% vs. 0%). There was a significantly increasing trend in yearly prevalence of equally credited author articles for all the journals (p < .0001 for all four journals). The first two authors received equal credit in most cases, and the practice was also found in nearly every position in the byline. The research institutions among the equally credited author articles were from various countries and regions around the world. Finally, none of the four journals provided specific guidance regarding this practice in their instructions to authors. CONCLUSIONS: It is increasingly common to give authors equal credit in original research articles in the major four journals of critical care medicine. A guideline for authors regarding when (and how) "equal" authorship should be assigned is warranted in future.