Objectives: To investigate gastric lavage (GL) cytopathology and immunometric analysis as novel clinicopathologic and prognostic parameters for gastric cancer (GC). Study Design: In 38 patients with gastric adenocarcinoma, we performed a cytopathologic analysis and an immunometric assay of GL using four tumor markers (CEA, CA 19.9, CA 72.4, and CA 50). The intragastric tumor marker levels were compared with a control group consisting of 41 non-GC patients to determine a statistically significant cutoff value. Results: GL cytopathology demonstrated the presence of cancer cells in 13 (34.2%) of the 38 GC patients: such a finding correlated to the parameters pT and pN with a statistically significant validity (p < 0.0267 and p < 0.0306, respectively). Measurement of intragastric CA 19.9 and CA 50 attained a statistically significant cutoff value (p < 0.002 and p < 0.0096, respectively), which was invalidated by the low sensitivity of the ROC curve analysis. Conclusions: In contrast to determination of its tumor markers, GL cytopathology correlated well with pT and pN staging parameters. Should this and other features be corroborated by future studies, the GL cytology test could be routinely used to detect aggressive types of GC even at early stages and result in important progress in the knowledge, staging, prediction, as well as management and follow-up of this inauspicious type of cancer.