The Early Learning Accomplishment Profile (Early LAP) provides a systematic method for observing children's functioning in the birth to 36-month age range in order to assist teachers, clinicians, and parents in assessing individual skills development in six developmental domains: gross motor, fine motor, cognition, language, self-help, and social emotional. This technical report describes the history of the Early LAP and its development, presents test administration guidelines, details the methodology and results of the Early LAP reliability and validity study, and reports statistical properties of the Early LAP. The report notes that the Early LAP was found to be reliable and valid in assessing the development of young children, with relatively high correlations between developmental age domain scores and chronological age, especially for children birth to age two. The Early LAP also evidenced good internal consistency and fairly low standard errors of measurement for each domain. Very good test-retest and interrater reliability were found for all domains. Evidence of adequate construct validity was also shown. The Early LAP had very good criterion validity, based on comparisons with the Bayley Scales of Infant Development-Second Edition. The report's appendix details the structure of early learning activity cards and citations for the 21 original sources of the Early LAP. (KB)