“…In Summary, the results shown on Tables (Table 10-15) indicate that capital structure, in general speaking has a negative and statistically significant influence on East African listed firm's financial performance at 5% significance level, which suggest that an increase in capital structure (STDR,LTDR and TDR) will result to a decrease in corporate financial performance (ROA and ROE).These results show that in average profitable listed firms in East African prefers to use internal source of financing in their capital structure as compared to external source of financing (like Debts-STDR,LTDR and TDR),the possible reasons for this situation is due several reasons such as Information asymmetry problems and financial markets in the East African region are still developing, hence it's difficult for profitable firms to access the external sources of financing (Like Corporate bonds), therefore decided to depend much on internal sources of financing (Like Bank borrowings) (Mwambuli,2015).Furthermore this results are supporting pecking order theory and our results are consistent with the findings of previous studies such as Kaumbuthu (2011), Karadeniz et al (2009), Zeitun & Tian (2007, Rao et al (2007), Huang & Sang (2006), Goddard et al (2005), Ngobo & Capiez (2004), Eriotis et al (2002), Fama & French (2002), Gleason et al (2000), Simerly & Li (2000), Majumdar & Chhibber (1999), Crnigol & Mramor (2009), Klapper & Tzioumis (2008), Dragota & Smenescu (2008), Song (2005), Chen (2004), Bauer (2004), Hall et al (2004), Deesomsak et al (2004), Cassar & Holmes (2003), Esperanca et al (2003), Nivorozhkin (2002), Shyam-Sunder & Myers (1999), Friend International Finance and Banking ISSN 2374-20892016, Vol. 3, No.…”