Investigations were made to prepare the inclusion compounds of the non-steroidal antiinflammatory drugs and additionally other slightly water soluble drugs with α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) in solid powdered form by the freeze-drying and the coprecipitation methods. The freeze-drying method was successful in obtaining the inclusion compounds of all the test drugs with β-CD and also some of them with α-CD by obtaining their aqueous solutions with addition of aqueous ammonia before the process, with a very good yield compared with the usual coprecipitation method. The drugs included by the coprecipitation method seemed to have fittable molecular sizes. The result showed that the coprecipitation method might be originally inferior to the freeze-drying method in obtaining the inclusion compounds of drugs in powdered form. It was shown by X-ray diffractometry that the inclusion compounds obtained by the freeze-drying method were amorphous. Clear differences in infrared (IR) absorption spectroscopy and differential calorimetry were observed between the inclusion compounds and the physical mixtures of drug/β-CD.