Background: Nutritional deficiencies are a concern after any bariatric surgery procedure. Restriction of oral intake and/or decreased absorption may cause vitamin abnormalities. Prevention of these vitamin deficiencies includes both supplementation and routine measuring of serum values. An investigation was undertaken to examine preoperative and short-term (1-year) postoperative levels of vitamins/trace minerals in patients undergoing laparoscopic Roux-en-Y gastric bypass (LRYGBP). Methods: Serum preoperative and postoperative vitamin/trace element levels of LRYGBP patients were recorded in a retrospective chart review (n = 100). Unavailable and undrawn levels were not included in the results. Results: Preoperative and 1-year postoperative percentage of abnormal levels were: vitamin A 11% and 17%, vitamin B12 13% and 3%, vitamin D-25 40% and 21%, zinc 30% and 36%, iron 16% and 6%, ferritin 9% and 3%, selenium 58% and 3%, and folate 6% and 11%. Conclusions: Abnormal vitamin and trace mineral values are common both preoperatively and postoperatively in a bariatric surgery patient population. Routine evaluation of serum levels should be performed in this specific patient population.