The interpretations of dilatometer test (DMT) field data for soil engineering properties are discussed in this paper. A PC version graphic FORTRAN program (DMTG) developed by the author at National Taiwan University is used for the DMT data reduction. A proposal to evaluate the behavior of laterally loaded piles using DMT data is presented. The concept of size effect and correction factors is included in the said proposal. An example of the evaluation of behavior of a laterally loaded pile using DMT data is clearly described. An assessment of the liquefaction potential of sands using both DMT lateral stress index (Kd) and cone penetration test (CPT) corrected cone bearing (Q‘c) is also presented in this paper. A parallel comparison of the liquefaction potential profile from both DMT and CPT data for sand layers is given in this paper.