Breast milk supplementation is frequently used to improve preterm infant growth and to achieve satisfactory intakes of minerals and vitamins. In the North American market there are commercial preparations: two powders and a liquid. The nutritional data available suggest these products are similar and their utilization is based on healthcare team choice. Parental perception about supplementation has not been previously evaluated although parental attitudes are known to impact on lactation success. The objectives of this paper are to determine parental preference and breastfeeding duration for very-low-birth-weight infants given commercial breast milk enrichment products. The study design is a randomized clinical trial with parental interviews. Sixty-three families with 71 infants were enrolled. Parents expressed their preference for the addition of a powder over a liquid preparation (p<0.01). Those mothers whose infants received the liquid enrichment had a shorter lactation relative to their goal, compared with the mothers of the infants who received the powder (p = 0.017). Parents prefer a powder product for breast milk supplementation and this choice positively impacts on the duration of breastfeeding for very-low-birth-weight infants.