Indoor mold after flooding poses health risks, including rare but serious invasive mold infections. The purpose of this study was to evaluate use of International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnosis codes for mold infection and mold exposure in Houston, Texas, during the year before and the year after Hurricane Harvey. This study used data from MarketScan, a large health insurance claims database. The incidence of invasive mold infections remained unchanged in the year after Hurricane Harvey; however, the incidence of diagnosis codes for mold exposure nearly doubled compared with the year before the hurricane (6.3 vs 11.0 per 100 000 enrollees, rate ratio: 1.7, 95% confidence interval 1.0-3.1). Diagnosis codes alone may not be sufficiently sensitive to detect changes in invasive mold infection rates within this population and time frame, demonstrating the need for more comprehensive studies.