&NA;The recent increase in incidence of deformational plagiocephaly is commonly believed to be associated with the American Academy of Pediatrics' “Back to Sleep” campaign. Other factors, however, may contribute to the development of this condition. During the past decade, we have seen a number of infants whose deformities seem to be associated with the extended use of car seats, infant carriers, bouncy seats, and infant swings. Having recognized that notes about usage were being routinely recorded in the margins of our clinical records, we began collecting information on the amount of time infants were spending in these devices. In this report, we describe our findings and document the related cranial deformities. The data and photographs were collected between 1998 and 2000 and reviewed to determine the amount of time children with deformational plagiocephaly spent in these devices. During the three‐year study period, 56.6% of the infants spent less than 1.5 hrs, 28.6% spent 1.5 to 4 hrs, and 14.8% spent more than 4 hrs/day in these devices. In addition, 5.7% slept in one of these devices during their first several months of life, frequently because of problems with reflux. These infants often developed an increase in posterior head height and “squaring” or “cornering” of the head. Normal use of car seats, carriers, swings and bouncy seats is not a concern; however, caution is warranted for infants who spend extended periods of time in these devices. The constant pressure these devices apply to the back of the cranium may perpetuate the deformation.