Habit faces of crystals of solution grown cyclotrimethylene trinitramine (RDX, cyclonite) are identified and dislocations characterised using the etch pit technique. The effects of nature of etchant and crystal history on etching are investigated and the dependence of etch pit shape on crystal face demonstrated. Observations by optical and scanning electron microscopy are used to study etch pit structure. The effects of thermal treatment and plastic deformation on dislocation glide and multiplication are examined and possible glide planes postulated.