The aspects of using optical instruments for minimally invasive interventions in abdominal surgery are considered. The results of clinical and preclinical trials of the application of the multimodal optical approaches in endoscopic instruments for the treatment and diagnosis of abdominal cancer are reviewed and discussed. A significant increase in image contrast, sensitivity, and specificity of cancer detection is noted. Novel fiber-optic system for versatile evaluation of the bile duct in patients with mechanical jaundice is described. It has been demonstrated that multimodal optical biopsy can be integrated with standard semi-automatic biopsy systems using fine-needle optical probes with immediate comparison of tumor and healthy tissue optical properties for determination of the tissue state. The applicability of this technique to the diagnosis of hepatocellular carcinoma has been demonstrated.