This work presents experimental as well as analytical studies of the behavior of laterally steel pile in a thick layer (17 meters) of soft clay. A lateral load test was performed to obtain experimental displacements in the field. This test was performed in two steel piles driven into a Recife organic clay deposit. The test was conducted in the experimental station of the UFPE Geotechnical Group (SESI-Ibura research site) in Recife, Pernambuco State, Brazil. The field results are compared to those obtained by linear and nonlinear finite element analysis. In this investigated area occurred a general rupture of a concrete structure on steel pile foundation due to horizontal displacement of the very soft organic clay deposit. The linear analysis was performed using a subroutine of beams and beam-columns on elastic foundation. The subroutine implemented in this work models the soil stiffness variation with depth as function of n_h (coefficient of horizontal subgrade reaction). The material and geometrical nonlinear analysis was performed in the pile-spring system by ANSYS commercial package. The nonlinear material soil behavior was modeled by p-y curves, obtained in this work by two methods, the fist proposed by Robertson at al. (1989) from dilatometer test and the other by Ménard et. al. (1969) from pressuremeter tests results. As a complement to Ghali's implementation (1989), it was developed a subroutine which adjusts geotechnical parameter n_h from experimental displacements results by a nonlinear least squares technique. The n_h determination was also done through Cintra and Albiero's method (1982), which is also based on experimental data. Estimates of the critical buckling loads for piles in soft organic soils for boundary condition are also presented.