Background & Aims: YKL-40 is a recently discovered humanglycoprotein which is related in amino acid sequence to the chitinaseprotein family, but has no chitinase activity .Increased levels of YKL-40 in serum have been described in many diseases running with inflammation such as rheumatoid arthritis, systemic lupus erythromatosus and Crohn's disease, and also in the group of cardiovascular diseases.Determination of the concentration of serum YKL-40 was also used in oncology.The tumors at various sites were found elevated levels of this marker in serum, as well as overexpression in tumor tissue. TRAIL (APO-2 ligand) is a transmembrane (type II) glycoprotein that belongs to the TNF superfamily. It is now accepted that TRAIL selectively induces apoptosis in tumor cells but not normal cells.The present work aim to clarify if both markers YKL 40 & TRAIL could be used as biomarkers of solid tumors and the occurrence of metastasis to find the role of apoptosis in the pathogenesis of this tumors and their metastasis (as YKL 40 is antiapoptotic & TRAIL as apoptotic protein), and to find a relation between both.Patients & Methods: The present study included 60 Egyptian people (30 Males and 30 females) age (25-80 years), recruited form National Cancer Institute in the period from 1st to 14th April 2013. Diagnosis of cancer was suspected by history, positive clinical examination and confirmed by tissue piobsy. They were classified into: Non-metastatic cancer patients with or without lymph node affection (30 patients) and Metastatic cancer patients with distant, organ , metastasis (30 patients). 20 healthy subjects were also included and served as control.The quantitative detection of YKL 40 (CHI3L1) and TRAIL serum levels was performed using a commercially available enzyme linked immunosorbent assay (ELISA) kit provided by WKEA MED, Changchun, China.Results: there is statistical significant difference regarding YKL-40 and TRAIL levels between the control group versus non-metastatic group as well as metastatic group (P value= 0.000 for each ). Conclusion: We concluded that there is significantly elevated serumYKL-40 level in cancer patients compared healthy controls, and there is significantly decreased serum TRAIL level in cancer patients compared healthy controls