Background:Trends in patient concerns can identify systematic problems in health care delivery that may not be detected when addressing individual concerns. It can be difficult identifying trends without using a standardized taxonomy. The study objectives were to describe patient complaints from a tertiary care pediatric hospital and categorize them using a standardized complaint taxonomy.Methods:Physician-based patient complaints were compiled from April 2011 to May 2014 from a tertiary pediatric hospital. These complaints were coded independently by 2 reviewers using the Reader taxonomy, a published standardized taxonomy. Complaints were placed into 3 domains: clinical, management, and relationships then organized into categories. Inter-rater reliability for domain classification between the 2 reviewers was calculated using Cohen’s unweighted κ.Results:Eighty-seven patient complaints were identified, representing approximately 1 per 10,000 physician–patient encounters. Half (48/87) were related to care in the emergency department. When adjusted for volume, pediatric hospital medicine had the highest number of complaints, with 12.1 per 10,000 encounters. The majority of patient complaints, 66% (57/87), were of the clinical domain (κ = 0.61). Sixty percent (52/87) were in the relationship domain (κ = 0.68), and 16% (14/87) were in the management domain (κ = 0.65).Conclusions:We found a low overall complaint rate. Our results indicate that interventions to improve patient experience should initially be targeted at emergency and hospital medicine on the clinical and relationship domains. The inter-rater reliability of the Reader taxonomy was moderate with implications for processing patient complaints at a hospital level.