This paper reports part of the results of research on chemical problem solving behavior of pre-service teachers in Plateau and Northeastern states of Nigeria. Specifically, it examines and describes the methods used by 204 pre-service teachers in solving quantitative problems from four topics in chemistry. Namely, gas laws; electrolysis; stoichiometry and composition of substances. The pre-service teachers involved were 200 and 300 level Nigeria Certificate in Education (NCE) chemistry majors and non-majors. Data were collected from their written responses to four items of a chemistry problem solving Test (CPST) and retrospective interview. The frameworks adopted for analysing the methods used in solving the CPST items were those documented in the chemical education literature (Garafalo F. and Toomey R., (2002); Chemtutor, (2001); Danjuma I. M. and Akpan E. U. U., (2000), "Niger. J. Curric. Stud.," 7(2), 129-135). These are plug and chug; ratio and proportion; dimensional analysis; reaction chemical equivalence and simple algebra. The results of the data analysis revealed that most of the pre-service teachers have used the appropriate methods to solve the CPST items, except that, only a few got the correct answers. Most of them indicated that their main reason for using the method of choice was the nature of the problems. Also, most of them indicated that they were not aware of other methods of solving the problems. (Contains 4 tables.)