BACKGROUND: Poor communication of tests whose results are pending at hospital discharge can lead to medical errors. OBJECTIVE: To determine the adequacy with which hospital discharge summaries document tests with pending results and the appropriate follow-up providers. DESIGN: Retrospective study of a randomly selected sample PATIENTS: Six hundred ninety-six patients discharged from two large academic medical centers, who had test results identified as pending at discharge through queries of electronic medical records. INTERVENTION AND MEASUREMENTS: Each patient's discharge summary was reviewed to identify whether information about pending tests and follow-up providers was mentioned. Factors associated with documentation were explored using clustered multivariable regression models. MAIN RESULTS: Discharge summaries were available for 99.2% of 668 patients whose data were analyzed. These summaries mentioned only 16% of tests with pending results (482 of 2,927). Even though all study patients had tests with pending results, only 25% of discharge summaries mentioned any pending tests, with 13% documenting all pending tests. The documentation rate for pending tests was not associated with level of experience of the provider preparing the summary, patient's age or race, length of hospitalization, or duration it took for results to return. Follow-up providers' information was documented in 67% of summaries. CONCLUSION: Discharge summaries are grossly inadequate at documenting both tests with pending results and the appropriate follow-up providers.