Ganciclovir is an acyclic guanine nucleoside analog and is a well-known anti-viral agent that inhibits replication of herpes virus. Ganciclovir is reported to exhibit polymorphism. However, based on the previous studies on the polymorphs it was found that a thorough investigation for the polymorphs of Ganciclovir was required. We report the solid-state characteristics of four polymorphic forms, viz. form I, form II, which are anhydrous, and form III, Form IV, which are hydrates. These hydrates exist as hemihydrates and monohydrates. The physicochemical characteristics for the forms of ganciclovir have been performed using techniques such as powder X-ray diffraction, thermoanalytical methods, infrared, near-infrared spectroscopy, and variable-humidity and temperature powder X-ray diffraction.