When should a child's first check up be?

1-2 wks after birth. A child's first check up should occur 1-2 weeks after birth. If you are referring to an older child, the first check up should be now, then follow the recommendations of the pediatrician or family doctor for subsequent follow ups.
3-4 days. Babies get discharged usually after 24 h of life or by day 2 of life, babies should see their doctor within 3-4 days to make sure they aren't losing too much weight and to monitor for jaundice.
2-5 days old. Newborns, especially breastfed ones, should be seen ideally 48-72 hours after going home from the hospital. On a case by case basis some babies have their first check up later than that. At the minimum, all newborns should be seen at least once by the time they are 2 weeks old.
Well check ups... The AAP recommends 1 week old 2 months old 4 months old 6 months old 9 months old 12 months old 15 months old 18 months old then after with each birthday until 21 years old then will be referred to a Family Physician or Internist.