For a study, researchers sought to determine how the number of restored lymph nodes was affected by intra-arterial indigo carmine injection following transanal full mesorectal excision. This study employed retrospective, non-randomized research. The investigation was done by an interdisciplinary team of investigators at a tertiary hospital. Patients who underwent transanal full mesorectal excision for probable rectal cancer between 2013 and 2019 were included in the study. Indigo carmine was intravenously injected ex vivo to color the lymph nodes on rectal cancer tissues. One of the outcome measures was the number of recovered lymph nodes that were stained or unstained. About 189 patient samples were examined, 108 of which (57.1%) had indigo carmine stains. In stained samples, a mean of 19.8 plus minus 6.1 lymph nodes were found as opposed to (16.0± 4.9) in unstained samples (P<0.001). In stained specimens, 3.2 extra lymph nodes were discovered, according to multivariable analysis (95% CI: 1.0 to 5.3; P=0.02). In stained specimens, the appropriate lymph node count (≥12) rose in univariable analysis but not in multivariable analysis (odds ratio: 3.24, 95% CI: 1.13 to 10.65; P=0.03). Injection of indigo carmine had no impact on the number of lymph nodes that were positive or the nodal stage. Chemoradiotherapy caused a 2.5percent decrease in lymph node count (P=0.008). About 95% of chemoradiotherapy patients had less than 12 lymph nodes removed after staining. The average patient follow-up was 24.2 months, and the local recurrence rate was 3.3%. The study was constrained by the nonrandomized allocation and retrospective approach. After transanal complete mesorectal excision, ex vivo intra-arterial indigo carmine injection increases the number of isolated lymph nodes regardless of neoadjuvant chemoradiotherapy. Nodal upstaging or a rise in the number of lymph nodes that are tumor-positive were not linked to indigo carmine injection.