Abstract: The nuclear magnetic resonance spcclra of the compounds with the formula H_mF_2-mSi(CH₂CH₃)_n(CHCH₂)_2-n are investigated, where m and n represent the integers 0,1 or 2. For monofluoro-compounds the coupling constant J_HFis 52.2Hz. Because of the effect of fluorine atom on the protons, of Si-H, Si-CHCH₂, Si-CH₂- and CH₃, their chemical shifts have a downficld shift of 0.60-1.00, 0.15, 0.05-0.15 and 0.10ppm, respectively, from their parents. Subsequent to the substitution of ethyl by vinyl groups the chemical shift of Si-Hprotons has downfield shift of 0.20-0.60 ppm from the parents. But no significant effect can be observed on other protons. The three protons in vinyl group possess the same chemical shift values.