Although articles in series generally embrace a central theme, they may not share a common index term; retrieval by medical subject heading often produces an incomplete set. Since subject retrieval is problematic, it would be helpful if articles in a series could be retrieved by series title. Five quality-assessed general medical journals published in 1993 were examined revealing 134 series. The retrieval effectiveness of series titles was measured utilizing formulas for recall and precision in the Medline and SciSearch databases. Mean recall of articles in series from both databases was 23% and mean precision was 25%. Although the mean difference between Medline and SciSearch recall was .07, the slight positive difference exhibited by Medline was not statistically significant. Correlation coefficients demonstrate a positive rather than inverse relationship between recall and precision for both databases. Mean recall of series with attached titles (a title-subtitle configuration) was 94% and unattached titles (journal section title-article title configuration) was 11%. These results demonstrate both databases adhere to documentation pertaining to articles in series. Three editions of "Guide to Special Issues and Indexes of Periodicals" were examined for background information on the indexing of articles in series. Nine figures and eight tables present information. (Contains 61 references.) (AEF)