Purpose: The prevalence of molar incisor hypomineralization in the United States is unknown. The condition is defined via the presence of demarcated opacities of varying color, porous enamel, advanced susceptibility or progression of dental caries, and sensitivity. The purpose of this study was to establish the prevalence of molar incisor hypomineralization (MIH) in Pittsburgh, Pa., USA. Methods: A total of 104 patients (64 females and 40 males ranging in age from seven to 32 years) from the University of Pittsburgh were screened for the clinical signs of MIH between May 15 and July 31, 2019. MIH was defined according to international guidelines. Results: A total of 9.6 percent of patients screened presented with the clinical signs of MIH; 15.4 percent of patients screened presented with clinical signs aligning with dental fluorosis. Conclusions: Molar incisor hypomineralization is prevalent and clinically relevant in Pittsburgh. American clinicians should start recording the diagnoses of MIH to facilitate establishing national prevalence data and increase knowledge and treatment.