Background: Malnutrition is a major complication of head and neck cancer and has pertinent implications on survival. Methods: We performed a retrospective analysis of 320 patients with head and neck cancer from a tertiary hospital in Western Australia from 2013 - 2021. Weight and albumin were collected from different timepoints in the patient’s journey, including at diagnosis and end of treatment. Treatments received, recurrences and survival data were also collected. Initial univariate analyses were performed using Chi squares. Results: Median follow-up was 2.6 years (range 16 days to 9 years). 44% of patients underwent curative intent radiotherapy or chemoradiotherapy, 38% had surgery (+/- adjuvant therapies), 9% had palliative treatments, and 9% had best supportive care. At diagnosis, 12% of patients were hypoalbuminemic, 75% had normal albumin, and albumin was unknown in 13%. Hypoalbuminemia at diagnosis strongly correlated with lower survival compared with patients with normal albumin with 1 year OS (1YS) 35% vs 82% (p < 0.00001). Patients with normal albumin at diagnosis had higher disease-free survival compared to hypoalbuminemic patients (56% vs 32%, p = 0.04). By the end of treatment, 22% of patients were hypoalbuminemic, 48% had normal albumin, and 30% were unknown. Hypoalbuminemia at end of treatment was also prognostic, with 1YS 72% vs 89% and 2YS 52% vs 72% (p = 0.002) when compared to patients with normal albumin. Of patients who were treated with curative intent, there was no significant difference in the rate of relapse (38% vs 35%, p = 0.67). By Body Mass Index (BMI) at diagnosis, 5% of patients were severely underweight (BMI < 16.5), 7% underweight (BMI 16.5-18.4), 34% healthy (BMI 18.5-24.9), 31% overweight (BMI 25.0-29.9), and 22.5% obese (BMI ≥30). BMI at diagnosis was highly prognostic with 1YS 37% in severely underweight patients, 67% underweight, 75% healthy, 91% overweight, and 94% in obese individuals (p < 0.00001). By end of treatment, 7% were severely underweight, 9% were underweight, 42% were healthy, 28% were overweight, and 14% were obese. Low BMI at end of treatment was also associated with inferior outcomes with 1YS 53% in severely underweight individuals, 76% underweight, 83% healthy, 97% overweight, and 95% in obese patients (p < 0.00001). Median weight loss from diagnosis to end of treatment was 6kg (range from 34kg loss to 15kg gain), and median % body weight change was -7.5% (range from -28% to +26%). Percentage body weight loss of > 20% was associated with worse survival with 65% mortality during the study period compared with 35% in patients who lost ≤20% body weight. 1YS was 71% in patients who lost > 20% body weight compared to 86%, although this did not reach statistical significance (p = 0.097). Conclusions: Hypoalbuminemia and low BMI at diagnosis and end of treatment, in addition to % body weight loss of > 20% were all associated with worse survival in head and neck cancer patients.