This research aims to know the effectiveness of Think-Talk-Write learning in increasing the student's ability in mathematical communication and disposition. The learning strategy was the problem-based learning strategy with the cooperative approach of TTW facilitated by a module. The method of the research was a quasi-experimental method; it was a research which its purpose to review the possibility of the increasing relation of mathematical communication and disposition as a result of applying the learning process by using the TTW strategy to the experiment group and the expository strategy in a control class. The design used in this research was a control group pretest-posttest. In this research the research subject werte given the pretest to measure their beginning ability. The subjects of this research were chosen randomly which were assumed that it would create two groups with the subject who had the similar abilities. By giving the pretest also it would convince the researcher if they had whether the similar or different abilities. The posttest was used to measure the ability in mathematical disposition and communication after applying the learning strategy. The subject of this research was the X student of the State Senior High School 1 Metro in the year of 2012/2013. The research was done for 10 meetings with its planning doing and evaluating the applying result of two classes which have relatively the same beginning ability such as class X.6 as the control class( the conventional learning of expository type) and class X.7 as a control class ( The TTW Learning strategy). The result of the research showed that the application of the cooperative learning strategy of TTW type was more effective in increasing the student's ability in mathematical communication and disposition if it was compared with conventional learning of expository type. It was supported by the posttest result of the student's ability in mathematical communication could reach the effectiveness ES = 1,032 which means that effectiveness of TTW strategy in increasing the student ability in mathematical communication was significant or high. Based on the result of student mathematical disposition questionnaire had reached the effectiveness ES = 0,681, it showed that TTW strategy was effective in increasing the student mathematical disposition compared to the expository learning.