The present study aimed to investigate haemoglobin (Hb) changes before and after packed red blood cell (RBC) transfusion in burn patients. This study was a retrospective cross-sectional study that was conducted on burn patients in Velayat hospital in Rasht, Iran. The sampling method of this study was consecutive sampling. Data were collected using patient records, including age, gender, body mass index (BMI), total body surface area (TBSA) percentage, length of hospitalisation, Frequency of receiving packed RBCs, and Hb level before each packed RBC transfusion and 4 to 6 hours after transfusion. Paired t tests and analysis of variance (ANOVA) were used to compare the study variables. Pearson's correlation coefficient was used to investigate the relationship between Hb changes after the transfusion of packed RBCs and the study variables. A total of 110 burn patients participated in this study. The average Hb before and after transfusion was 8.07 (SD = 0.97) and 9.16 (SD = 1.01), respectively, which were significantly different (P = .0001). The results showed that there was a significant negative relationship between the variables of age (r = -0.188, P = .0001), BMI (r = -0.110, P = .035), and TBSA percentage (r = -0.122, P = .019) with changes in Hb after transfusion. Also, the duration of hospitalisation had a significant positive relationship with Hb changes after transfusion (r = 0.124, P = .017). In sum, Hb level compensation through packed RBC transfusion in elderly burn patients has more challenges. The number of changes in Hb level after receiving packed RBCs decreased with increasing TBSA, BMI, and age. Also, there was a positive correlation between the duration of hospitalisation and changes in Hb levels.