Introduction There is a high prevalence of malnutrition among older adults entering residential aged care (RAC). Aim To determine whether 60 mL of a compact oral nutrition supplement (ONS; daily total: 576 kcal, 35 g protein) consumed four times daily with medication rounds improves malnutrition status, body weight, and body composition measures among older adults in RAC. Methods Residents (n = 20; mean age: 86.7 ± 6.8 years; 50% female) screened for malnutrition (20% malnourished, 80% at risk of malnutrition) using the Mini Nutritional Assessment-short form were recruited during April-June 2021. Participants received 60 mL of an ONS four times daily using the Medication Pass Nutrition Supplement Programme (Med Pass). The ONS intake and participant compliance were recorded. Body mass index, fat, and muscle mass (bioelectrical impedance), malnutrition risk, depressive symptoms, and quality of life were assessed at baseline and following the 18-week intervention. Results Median overall compliance was 98.6%. An ONS intake did not significantly increase mean ± s.d. any body composition measures or improve health and wellbeing outcomes; however, it resulted in increased body weight and body mass index (BMI; 13/20 (65%) participants), body fat mass and percentage (10/16 (63%) participants) and muscle mass (9/16 (56%) participants). Malnutrition risk scores improved in 65% (13/20) of participants, resulting in 10% being assessed as malnourished, 65% at risk of malnutrition, and 25% with normal nutrition status. Discussion Delivery of a compact oral nutrition supplement with the medication round was accepted by residents. Its efficacy in improving malnutrition risk and body composition among residents warrants further investigation.