Marine oil and gas pipelines are characterized by several special features (in addition to general requirements for all pipeline tubes); these features are related with concrete operating conditions and need additional estimations in designing and construction stages. The paper observes production of electric longitudinal welded tubes via JCO-forming at Vyksa metallurgical works. The technique of conducting of certification testing of tubes 1220x36 mm and 1067x40 mm is described. The results of testings have shown that these tubes can be recommended for gas abd oil pipelines with operating pressure up to 25 MPa, construction temperature down to -60 ^oC and operating temperature down to -20 ^oC.