We construct a coherent state of q-deformed zero coupled nucleon pairs distributed in several single-particle orbits. Using a variational approach, the set of equations of qBCS theory, to be solved self consistently for occupation probabilities, gap parameter ∆, and the chemical potential λ, is obtained. Results for valence nucleons in nuclear degenerate sdg major shell show that the strongly coupled zero angular momentum nucleon pairs can be substituted by weakly coupled q-deformed zero angular momentum nucleon pairs. A study of Sn isotopes reveals a well defined universe of (G, q) values, for which qBCS converges. While the qBCS and BCS show similar results for Gap parameter ∆ in Sn isotopes, the ground state energies are lower in qBCS. The pairing correlations in N nucleon system, increase with increasing q (for q real). The problem of nucleon pairing has been of great interest to those interested in solving the riddles about nuclear structure. BCS theory of superconductivity [1] turned out to be a great ally in efforts to take in to account short range interactions between nucleons. In many nuclear structure calculations BCS is taken as the starting point as the BCS wave function offers a good approximation to ground state of even-even nuclei. Another approach to nucleon pairing problem is the seniority scheme. In order to include the pairing correlations left out in these approximate schemes, we studied the zero coupled nucleon pairs with q-deformations [2] expressing these in terms of the generators of quantum group SU q (2). The quantum group SU q (2), a q-deformed version of Lie algebra SU(2), has been studied extensively [3][4][5], and a q-deformed version of quantum harmonic oscillator developed [6,7]. The quantum group SU q (2) is more general than SU(2) and contains the later as a special case. The underlying idea in using the zero coupled nucleon pairs with q-deformations is that the commutation relations of nucleon pair creation and destruction operators are modified by the correlations as such are somewhat different in comparison with those used in deriving the usual theories. The seniority scheme for q-deformed nucleon pairs in a single j orbit and zero seniority states for nuclei with q-deformed nucleon pairs distributed over several orbits have also been constructed in Ref. [2]. On the same lines Random Phase Approximation equations for the pairing vibrations of nuclei have been derived and applied to study pairing vibrations in Pb isotopes [8]. Further a q-deformed version of quasi boson approximation for 0 + states in superconducting nuclei was developed. The q-deformed theories reduce to the corresponding usual theories in the limit q → 1. The Nucleon pairing in a single j shell has also been treated by Bonatsos et. al [9,10] by associating two Q-oscillators, one describing the J = 0 pairs and the other associated with J = 0 pairs. In their formalism, Q-oscillators involved reduce to usual harmonic oscillators as Q → 1 and the deformation is introduced in a way different from ours. Following...