This paper presents the main results obtained from an extensive laboratory investigation on Brazilian marine clays. Samples were collected from different depths in eight petroleum fields (Marlim, Marlim Leste, Marlim Sul, Espadarte, Jabuti, Jubarte, Cachalote and Roncador) located in Campos basin and one petroleum field (Piranema) located in Sergipe - Alagoas basin, offshore Brazil. Grain size analyses, Atterberg limits, oedometer tests, isotropically consolidated undrained compression (CIUC) and K₀-consolidated undrained compression (CK₀UC) triaxial tests, direct simple shear (DSS) and resonant column tests were carried out in samples from 56 cores. Moreover, in some of CIUC triaxial tests, maximum shear moduli (G_max) were determined by using bender elements inserted into the specimens. The SHANSEP technique was used in the investigation to study the undrained behavior of the marine clays. A summary of the main characteristics of compressibility, deformability and undrained strength (s_u) of the soils investigated is presented. Finally, a correlation between G_max values obtained with bender elements and s_u from CIUC tests is shown in the paper.