The investigation gives the comparison of performance of transverse and longitudinal tile drainage in excessively wet loamy soils in Latvia. The investigation has been conducted to determine the effect of longitudinal drainage and data which were obtained showed that if the slope of the surface land is i ≤ 5%, then the longitudinal drainage ensures the same soil drainage intensity as in the case of transverse drainage. However, longitudinal drainage in comparison with transverse drainage has several significant advantages in relation to construction technology and the operation of installed drainage layout system. In most cases, it is advisable to design the drains with the optimum slope (1-2%), not distinguishing between transverse and longitudinal drainage. The paper indicates cases when longitudinal drainage is not advisable.