Abstract In this paper, we obtain analytical solutions of an unsolved integral 𝐑 S ⁢ ( m , n ) {𝐑_{S}(m,n)} of Srinivasa Ramanujan [S. Ramanujan, Some definite integrals connected with Gauss’s sums, Mess. Math. 44 1915, 75–86] with suitable convergence conditions in terms of Meijer’s G-function of one variable, by using Mellin–Barnes type contour integral representations of the sine function, Laplace transform method and some algebraic properties of Pochhammer’s symbol. Also, we have given some generalizations of Ramanujan’s integral 𝐑 S ⁢ ( m , n ) {𝐑_{S}(m,n)} in the form of integrals ℧ S * ⁢ ( υ , b , c , λ , y ) {℧_{S}^{*}(υ,b,c,λ,y)} , Ξ S ⁢ ( υ , b , c , λ , y ) {Ξ_{S}(υ,b,c,λ,y)} , ∇ S ⁡ ( υ , b , c , λ , y ) {∇_{S}(υ,b,c,λ,y)} and ℧ S ⁢ ( υ , b , λ , y ) {℧_{S}(υ,b,λ,y)} with suitable convergence conditions and solved them in terms of Meijer’s G-functions. Moreover, as applications of Ramanujan’s integral 𝐑 S ⁢ ( m , n ) {𝐑_{S}(m,n)} , the three new infinite summation formulas associated with Meijer’s G-function are obtained.