We　consider　the　problem　of　variable　selection　for　a　class　of　varying　coefficient　models　with　instrumental　variables.　We　focus　on　the　case　that　some　covariates　are　endogenous　variables,　and　some　auxiliary　instrumental　variables　are　available.　An　instrumental　variable　based　variable　selection　procedure　is　proposed　by　using　modified　smooth-threshold　estimating　equations　(SEEs).　The　proposed　procedure　can　automatically　eliminate　the　irrelevant　covariates　by　setting　the　corresponding　coefficient　functions　as　zero,　and　simultaneously　estimate　the　nonzero　regression　coefficients　by　solving　the　smooth-threshold　estimating　equations.　The　proposed　variable　selection　procedure　avoids　the　convex　optimization　problem,　and　is　flexible　and　easy　to　implement.　Simulation　studies　are　carried　out　to　assess　the　performance　of　the　proposed　variable　selection　method.　(C)　2012　Elsevier　B.V.　All　rights　reserved.