BACKGROUND: There are no reports in the transfusion medicine literature that describe adverse reactions and donor arm injuries after whole-blood donation based on solicited information. STUDY DESIGN AND METHODS: The present study solicited adverse reaction and donor arm injury information from 1000 randomly selected whole-blood donors approximately 3 weeks after the whole-blood donation. Two 16-gauge phlebotomy needles in use were also compared. RESULTS: Thirty-six percent of the donors had one or more adverse effects (AEs). The most common systemic AEs were fatigue (7.8%), vasovagal symptoms (5.3%), and nausea and vomiting (11.1%). The most common arm findings were bruise (22.7%), arm soreness (10.0%), and hematoma (1.7%). Men were half as likely as women to have an AE (23% AE vs. 48% AE, p < 0.0001). Repeat blood donors had fewer AEs than first-time blood donors (36% AE vs. 47% AE, p < 0.007), and African-American donors had numbers of AEs similar to those of Caucasian donors (31% AE vs. 38% AE, p = 0.30). The two phlebotomy needles did not differ in causing blood donor AEs. CONCLUSION: AEs after donation and complaints may be more common than previously thought. The postdonation interview is a good tool for defining the blood donor's experience. It can also be used to evaluate and potentially improve blood donor safety and comfort.