Background: Poverty and malnutrition are associated with the risk of developing tuberculosis (TB). Nutritional reintegration with anti-TB therapy may improve treatment success rate. Aim: To investigate the nutritional status of low-income pulmonary TB patients in relation to the different anti-TB treatment phases. Methods: Forty five pulmonary TB patients and 40 controls aged 19-54 years, receiving treatment at Infectious Disease Hospital, Calabar, Nigeria, between September 2018 and July 2019 were studied. Serum total protein, albumin, iron and vitamin A were determined by colorimetric and HPLC methods respectively. Height and weight were measured and BMI computed, and data analysed using Student’s t-test, ANOVA, and Pearson’s correlation at P<0.05. Results: Among TB patients, 66.7%, 35.5%, and 22.22% were albumin, iron, and vitamin A deficient respectively. Total protein and globulins levels were higher while BMI, albumin, iron, and vitamin A were lower in the TB patients compared to the control (P=0.001). Albumin and iron levels of TB patients on continuation phase of anti-TB treatment (CPAT) were higher than those of TB-HIV coinfection on the same phase of treatment, TB patients on intensive phase of anti-TB treatment (IPAT) and controls (p<0.05). Comparing TB patients on CPAT and IPAT, also CPAT-HIV and IPAT-HIV patients, BMI and biochemical indices studied were not significantly different (P>0.05) respectively. Albumin and iron were significantly lower in CPAT-HIV compared with CPAT patients. Albumin correlated positively and significantly with iron (r=0.405, p=0.006) in TB patients. Conclusion: Tuberculosis is associated with decreased BMI, albumin, iron and vitamin A, and higher total protein, and globulin, suggesting that malnutrition may be associated with TB risk, poor treatment compliance and outcomes.