Over the past 10 years, identification of Autism Spectrum Disorder (ASD) risk has dramatically increased due to the wide-spread implementation of screening programs; yet, there is limited understanding about parent perceptions and experiences during the time period when risk is identified, but prior to receiving a formal diagnosis--a period that can last months to years given the long wait-lists for formal ASD evaluations. The current study aimed to examine parent perceptions of family impact (i.e., the impact their child's behaviors have on the family) between the time of risk-identification and formal diagnosis among 277 children identified as at-risk for ASD through screening positive in primary care. We aimed to compare family impact among those whose child met diagnostic criteria for ASD and those who did not. Parents of children who received a non-ASD diagnosis reported a higher baseline level of family impact (F[1, 274] = 5.82, p = 0.017); however, perceived difficult child behavior was a stronger predictor of family impact (t[6] = 13.11, p < 0.001) than later diagnostic group (t[6] = - 2.10, p = 0.037), and child functioning did not predict family impact (t[6] = -0.31, p = 0.76). These results suggest that in this population, perceived difficult child behavior is a stronger predictor of family impact than later diagnostic category and should be considered an important factor in family support.