Socially-responsible business and ethical behavior of companies have been of interest to academia and practice for decades, but the focus has almost exclusively been on large corporations, while small and medium-sized enterprises (SMEs) have not received as much attention (Hammann, et al., 2009). Worthington, et al (2006 recognized the need to encourage socially-responsible business practices among the 90 per cent or more of the world's businesses that are classified as SMEs. Perrini, et al (2007) found that size explains the differences in firms' willingness to define and implement such specific corporate social responsibility (CSR) strategies, while Murillo and Lozano (2006) concluded that it still remains to be explored whether manufacturing companies tend to apply CSR more extensively, or whether businesses oriented to other business have a tendency to incorporate CSR into their management patterns to a higher degree. Moreover, President Gloria Macapagal-Arroyo, in her 7 June, 2002 speech, recognized the importance of Chinese-Filipinos in helping improve the Philippine economy, and yet, not much research had been done on this sub-sector. Thus, this paper focuses on the effect of firm size and firm activities on the social responsibility practices of selected 30 micro, small and medium-sized enterprises (MSMEs) in Metro Manila which are owned by Chinese-Filipinos. Survey questionnaires and interview were used for gathering data, while a correlations test was used to analyze the data and to conclude whether firm size and firm activities have an effect on the sampled companies' CSR practices.