Spatially resolved electrical and spectroscopic behavior around isolated grown‐in dislocation inp‐type undoped GaAs crystals grown by liquid‐encapsulated Czochralski technique is investigated. Surface spreading resistance is found to remarkably increase at about 100 &mgr;m in diameter around dislocations. In a corresponding area, photoluminescence intensity of the 1.49‐eV and 1.44‐eV acceptor level peaks decreases. However, that of 0.8‐eV deep level peak does not vary. These results demonstrate that dislocations should give rise to carrier density variation due to the relative concentration change of levels around them.