The objective was to assess the vitamin D status in healthy 12-month-old infants in relation to quantity and sources of dietary vitamin D, breastfeeding and seasons. Subjects were 76 12-month-old infants. Serum levels of 25-hydroxyvitamin D (25(OH)D) ≥ 50 nmol/L were considered indicative of vitamin D sufficiency and 25(OH)D < 27.5 nmol/L as being indicative of increased risk for rickets. Additionally, 25(OH)D > 125 nmol/L was considered possibly adversely high. Total vitamin D at 9-12 months (eight data collection days) included intake from diet and supplements. The mean ± SD of vitamin D intake was 8.8 ± 5.2 μg/day and serum 25(OH)D 98.1 ± 32.2 nmol/L (range 39.3-165.5). Ninety-two percent of infants were vitamin D sufficient and none at increased risk for rickets. The 26% infants using fortified products and supplements never/irregularly or in small amounts had lower 25(OH)D (76.8 ± 27.1 nmol/L) than the 22% using fortified products (100.0 ± 31.4 nmol/L), 18% using supplements (104.6 ± 37.0 nmol/L) and 33% using both (110.3 ± 26.6 nmol/L). Five of six infants with 25(OH)D < 50 nmol/L had no intake of supplements or fortified products from 0 to 12 months. Supplement use increased the odds of 25(OH)D > 125 nmol/L. Breastfeeding and season did not affect vitamin D status. The majority of infants were vitamin D sufficient. Our findings highlight the need for vitamin D supplements or fortified products all year round, regardless of breastfeeding.