BACKGROUND: More than 60% of the active pharmaceutical ingredients, which are classified as Biopharmaceutics Classification System class II. The limited solubility of these drug may lead to low therapeutic effects. METHODS: Nanoprecipitation presents some advantages because it is a straightforward method with low-cost equipment that is easy to scale up. RESULTS: However, there are two technical issues of concern related to this method. First, the two solvents used for this approach must be miscible; concomitantly, the drug has to be soluble enough in a solvent but not in the antisolvent. Second, the particle growth needs to be adjusted by surfactant addition. CONCLUSION: In this review, nanoprecipitation methods and solvent removal techniques for poorly water soluble drugs will be discussed.