Mathematical Communication Skills (MCS) refer to the students' ability to (1) arrange and link their mathematical thinking through communication; (2) communicate their logical and clear mathematical thinking to their friends, teachers, and others; (3) analyze and assess mathematical thinking and strategies used by others; and (4) use mathematical language to express mathematical ideas correctly. Referring to the importance of MCS in mathematics problem-solving, this study was intended to analyze students' mathematical communication skills in solving a mathematics problem. This study employed a case study design with the participants of the study were 3 students of the eighth-grade of Junior High School in Indonesia. The data of this study was dug up through observation, documentation, and interview. The findings reveal that only 1 out of 3 students' is able to express mathematical ideas; understand, interpret and assess or respond to mathematical ideas; and use terms, notations, and symbols to present mathematical ideas. This study implies that the students' mathematical communication skills are still needed to be developed. This study should be taken into account by the Mathematics teachers to not only teach mathematics but also stimulate the students' mathematical communication skills through creative and innovative learning activities.