Pain is a hallmark sign of sickle cell disease (SCD) with more than 80% of vaso-occlusive episodes managed at home. This study explored the pyschometric properties of a daily pain and symptom diary and compliance of caregiver report in young children with SCD during a 1- to 2-year period. Compliance for completing diary entries for the first year with 16 caregivers was 90.6% and 86.2% with 19 respondents for the first 2 years. A Cronbach alpha of 0.86 was calculated for 12 items in the diary during a period of 1,450 diary days. Test-retest reliability analysis yielded 99.8% agreement between written entry and stated data entry. Interitem correlations for the 16 respondents ranged from 0.11 to 0.89 (mean, 0.52). Scale reliability estimates were quite strong, ranging from 0.50 to 0.99 (mean, 0.85). Construct validity was supported with significant relationships between caregiver report of giving medications when SCD pain was identified (chi-square = 98.0, P < .0001) and providing other help to relieve SCD pain (chi-square = 8.36, P < .004). The results provide evidence that the Infant/Toddler Diary is a reliable, valid measure of pain and illness report by caregivers of young children with SCD.