The purpose of this study was to collect normative data for individuals, aged 6 to 19 years, on the Box and Block test of manual dexterity. Four hundred and seventy-one subjects (231 females and 240 males) were recruited from the seven county Milwaukee area. The subjects were from urban, suburban, and rural settings thus encompassing a wide range of socioeconomic backgrounds. Data were stratified into seven age groups of two year intervals. Results showed that increases in manual dexterity coincided with increases in chronological age. Female scores were generally better from 6 to 11 years, while males achieved slightly higher scores from 12 to 19 years. On the average right and left hand dominant subjects scored higher with their right hands although right handers were clearly more lateralized than left handers.