In order to evaluate the effect of early human malnutrition (EHM) on waking and sleep organization, a group of 12 infants malnourished (M) from birth were investigated in their first year of life through 24-h polygraphic recordings. The same infants were recorded again after nutritional rehabilitation (R). A group of 12 age-paired normal infants served as controls (C). Both young (less than 4 months) and older (greater than or equal to 4 months) M infants showed a distribution of classes of waking duration different from that of C while the trend with age of the longest sustained waking (LSW) is similar in M and in C infants. The durations distribution of sleep episodes does not differ between M and C infants, while the longest sustained sleep (LSS) is significantly shorter in M than in C infants. The LSW is less clearly located in the day-time and the LSS is less clearly located in the night-time in M infants as compared to C infants. The quiet sleep-paradoxical sleep cycles are significantly shorter in older M infants because of the reduction of quiet sleep. Nutritional rehabilitation tends to improve waking and sleep organization.