The diagnostic decision-making standards used by practicing clinicians to determine language impairment were investigated. Randomly selected ASHA members who worked with children were asked to review hypothetical and real case profiles of children ages 4 to 9:11 (years: months) with language performance skills ranging from slightly above average to substantially below average. Based on the child's age and language and intelligence test information, clinicians were asked to decide if the child was language impaired (LI) and, if so, to provide a severity rating. Results show significant interrater agreement among the 27 clinicians' LI decisions (generalized kappa = 0.14, p < .0001) and moderate intrarater reliability within clinician's LI decisions (phi = .68). Most of the clinicians' diagnostic decision-making standards could be modeled using stepwise logistic regression. These decision rules can provide guidance for those who wish to employ diagnostic standards that reflect those used in clinical practice. Also, these results provide insight into the manner in which clinicians use information for the determination of language impairment.