Sums of the form Sigma(n)(k=0) Pi(p)(i=1) (a(i))(k)/Pi(q)(j=1) (b(j))(k) w(k) F-k (z) are considered, where F-k(z) are special functions of hypergeometric type. Such sums involving Bessel, Struve, incomplete gamma functions, and Laguerre, Hermite, Jacobi, Legendre, and Chebyshev polynomials can be represented in terms of the Kampe de Fe riet and generalized Horn hypergeometric functions of two variables.