We describe the development and preliminary psychometric testing of the Daily Activities of Infants Scale (DAIS), a parent-completed measure of opportunities parents provide infants for development of postural control and movement. First we obtained 1300 photographs of typical activities from 17 families with infants aged 4 to 11 months. Through consensus we established nine dimensions of activities, graded across three levels of opportunity for development. Pilot testing supported content validity of the DAIS. Subsequently, 50 parents of infants born preterm aged 4 to 11 months participated in psychometric testing. There were 25 male and 25 female infant participants with a mean gestational age of 29.4 weeks (SD 3.6) and a mean birthweight of 1266 grams (SD 635). We found that completion of the DAIS over 1 day was representative of data collected over 3 sequential days. Older infants obtained significantly higher DAIS scores than younger infants, providing preliminary evidence for discriminant validity. The DAIS scores demonstrated a part-correlation of 0.20 (p<0.01) with scores on the Alberta Infant Motor Scale obtained concurrently, providing some evidence for convergent validity. The intraclass correlation coefficients reflecting interrater reliability and test-retest reliability of the total DAIS score were 0.76 (95% confidence interval [CI] 0.60-0.86) and 0.77 (95% CI 0.60-0.87) respectively. The DAIS has sufficient reliability and validity for use in clinical practice and research.