The growing numbers of street children is one of the most serious social problems of the urban areas of the world. In Ethiopia it is estimated that there are more than hundred thousand street children. These children are engaged to varying degrees of street life. Higher proportion of these children are concentrated in Addis Ababa and other big cities such as Mekelle. Mekelle is one of the oldest cities of Ethiopia which was established during the second half of the nineteenth century and was a Capital of Ethiopia while Yohannes the 4th was the emperor. This survey had an aim of producing updated baseline information that helps to address the real problem of street children including the root causes and possible solutions. In this study, three different types of instruments are used; census questionnaire, survey questionnaire to the street children, and survey questionnaire prepared to the parents. Accordingly, the census result shows that there are 3121 street children in Mekelle; out of which 16.1% are females. Results show that economic factors are the main causes for two-third of the street children to move out to the streets.