Objective: Little is known about the prevalence and clinical presentation of avoidant restrictive food intake disorder (ARFID) in preschool children, and well-validated, parent-reported screening tools are lacking. This study evaluated the diagnostic validity of the parent-reported ARFID-Brief Screener in preschool children and examined prevalence and clinical characteristics of ARFID. Method: Parents of 645 children (50.5% male, mean age 3.2 years) completed the ARFID-Brief Screener in connection with the 2.5- and 4-year routine check-ups at 21 child health services centers in West Sweden. Parents of all screen-positive and of randomly selected screen-negative children were invited to a clinical follow-up interview via phone. Co-occurring neurodevelopmental problems were assessed via questionnaire, clinical examination, and health care records. Results: Of 42 (6.5%) children screening positive for ARFID, 29 were followed up via interview, and ARFID diagnosis was confirmed in 21 (positive predicted value 72%; other diagnostic metrics: negative predictive value 94%, sensitivity 91%, specificity 79%, and overall accuracy 84%. The adjusted prevalence of ARFID was 5.9%. All children with ARFID presented with both sensory-based avoidance and low interest, and the majority (65.2%) met criteria solely through DSM-5 criterion A4 (marked interference with psychosocial functioning). The ARFID group had significantly more co-occurring neurodevelopmental problems. Discussion: ARFID is not rare among preschoolers, although prevalence might have been slightly overestimated here. The ARFID-Brief Screener showed high diagnostic validity, but follow-up assessments are necessary to confirm diagnoses and reduce false positives. Co-occurring neurodevelopmental problems were common in ARFID and may serve as early markers of increased ARFID risk.