The American Academy of Pediatrics recommends regular developmental screening as a part of routine child health supervision. However, the pediatrician has a limited number of tools available to further evaluate a child who is found to be suspect or abnormal on a developmental screening test. The Clinical Adaptive Test/Clinical Linguistic and Auditory Milestone Scale (CAT/CLAMS) was therefore developed to provide pediatricians with a technique to assess infants and toddlers with suspected developmental delay. The CAT/CLAMS demonstrated strong psychometric properties. Concurrent validity with the Bayley Scales of Infant Development (BSID) was demonstrated in 43 children ages 12 to 19 months who were tested on three occasions with both instruments (correlation coefficient ranging between 0.63 and 0.87; P < .001). Predictive validity 6 and 12 months later was also demonstrated in this population with correlation coefficients ranging between 0.73 and 0.77, significant at the P = .001 level. Utilizing the CAT/CLAMS as part of the pediatrician's evaluation of children with developmental concerns would allow the pediatrician to compare language and nonlanguage problem-solving abilities and, therefore, aid in diagnosis and appropriate referral.