The addition reactions of cysteine without blocking amino and carboxyl groups to substituted and unsubstituted ${\beta}$-nitro-styrene derivatives were investigated. ${\beta}$-Nitrostyrene(1a), p-methyl-${\beta}$-nitrostyrene(1b), 3,4,5-trimethoxy-$[\beta}$ -nitrostyrene(1c), $[\varpi}$-3,4-methylenedioxy-${\beta}$ -nitrostyrene(1d), o-, m- and p-chloro-${\beta}$ -nitrostyrene (1e, 1f, 1g) and o-, m- and p-methoxy-${\beta}$-nitrostyrene (1h, 1i, 1j) easily undergo addition reactions with cysteine to form S-(2-nitro-1-phenylethyl)-L-cysteine(3a), S-[2-nitro-1-(p-methyl)phenyl-ethyl]-L-cysteine(3b), S-[2-nitro-1-(3',4',5'-trimethoxy) phenylethyl]-L-cysteine(3c), S-[2-nitro-1-($[\vatpi}$ -3',4'-methylenedioxy)phenylethyl]-L-cysteine(3d), S-[2-nitro-1-(o-chloro)phenylethyl]-L-cysteine(3e), S-[2-nitro-1-(m-chloro)-phenylethyl]-L-cysteine(3f), S-[2-nitro-1-(p-chloro)phenylethyl]-L-cysteine(3g), S-[2-nitro-1-(o-methoxy)phenylethyl]-L-cysteine(3h), S-[2-nitro-1-(m-methoxy)phenylethyl]-L-cysteine(3i) and S-[2-nitro-1-(p-methoxy)phenylethyl]-L-cysteine(3j), respectively. The structure of adducts were confirmed by means of UV-spectrum, IR-spectrum, molecular weight measurement and elemental analysis. The various factors effecting the yield of cysteine adducts to ${\beta}$-nitrostyrene derivatives were also studied.