The objective of this study was to characterize analgesic medication errors and to evaluate their association with patient harm. The authors conducted a cross-sectional analysis of individual medication error incidents reported by North Carolina nursing homes to the Medication Error Quality Initiative (MEQI) during fiscal years 2010-2011. Bivariate associations between analgesic medication errors with patient factors, error-related factors, and impact on patients were tested with chi-square tests. A multivariate logistic regression model explored the relationship between type of analgesic medication errors and patient harm, controlling for patient- and error-related factors. A total of 32,176 individual medication error incidents were reported over a 2-year period in North Carolina nursing homes, 12.3% (n = 3949) of which were analgesic medication errors. Of these analgesic medication errors, opioid and nonopioid analgesics were involved in 3105 and 844 errors, respectively. Opioid errors were more likely to be wrong drug errors, wrong dose errors, and administration errors compared with nonopioid errors (P < .0001 for all comparisons). In the multivariate model, opioid errors were found to have higher odds of patient harm compared with nonopioid errors (odds ratio [OR] = 3, 95% confodence interval [CI]: 1.1-7.8). The authors conclude that opioid analgesics represent the majority of analgesic error reports, and these error reports reflect an increased likelihood of patient harm compared with nonopioid analgesics.