Micrometastasis is a microscopic (less than 2 mm) deposit of malignant cells separated from the primary tumor. The incidence and importance of occult perigastric lymph node involvement were analyzed in 26 pN0 patients using the prospective method. The occult lymph node involvement was detected by immunohistochemical method using the anticytokeratin 8/18 antibody. Prevalence of clinically significant occult lymph node involvement (Mi+) was statistically significant, and found in 38.5% of pN0 patients. Out of tumor characteristics analyzed as possible predictors of occult lymph node involvement, the histological grade (GH) and the involvement of lymphatic vessels within gastric wall (pL1) had significant effect on the respective evaluation. The patients with histological grade 3 and 4 had occult lymph node involvement more often than those with grade 1 and 2 (p<0.05). More than 60% of pL1 patients had occult lymph node involvement LN (Mi+). Due to high prevalence of micrometastatic lymph node involvement, detection with specific immunohistochemical or molecular biology techniques should be a part of routine specimen examination in patients with pN0 gastric cancer.