We present here the necessary and sufficient conditions for the invertibility of tridiagonal matrices, commonly named Jacobi matrices, and explicitly compute their inverse. The techniques we use are related with the solution of Sturm-Liouville boundary value problems associated to second order linear difference equations. These boundary value problems can be expressed throughout a discrete Schrödinger operator and their solutions can be computed using recent advances in the study of linear difference equations. The conditions that ensure the uniqueness solution of the boundary value problem lead us to the invertibility conditions for the matrix, whereas the solutions of the boundary value problems provides the entries of the inverse matrix. Keywords: tridiagonal matrices, second order linear difference equations, Sturm-Liouville boundary value problems, discrete Schrödinger operator, Chebyshev functions and polinomyals 2010 MSC: 15B99, 31E05, 39A06 1. Preliminaries If we consider n ∈ N \ {0}, the set M n (R) of real matrices of size n × n, and the sequences a = {a(k)} n+1 k=0 ⊂ R, b = {b(k)} n+1 k=0 ⊂ R, and c = {c(k)} n+1 k=0 ⊂ R, then the Jacobi matrix associated with a, b and c is J(a, b, c) ∈ M n+2 (R) given