A total of 502 randomly selected incoming freshmen students were asked to answer Chemical Concepts Inventory questionnaire containing 22 multiple choice questions. These students graduated from a total of 150 private and public high schools. The sample is composed of 273 female and 229 male students. The Chemical Concepts Inventory developed by Mulford was meant to measure students’ conceptual understanding of common topics taken in a general chemistry class as well as alternate conceptions on these topics. Results indicated that these sampled high school graduates were not able to fully master some basic concepts in chemistry. Female and male students have mean scores of 4.63 and 4.75 respectively. Further analysis using t test of independent samples revealed that the mean scores did not differ significantly when students are grouped according to gender and type of school. This may indicate that these students did not fully understand the concepts covered in the inventory during their high school chemistry.