Pharmaceutical industry is constantly looking for ways to ensure and enhance product safety, quality and efficacy. However, drug recalls, manufacturing failure costs, scale up issues and regulatory burden in recent past suggest otherwise. In traditional quality by testing (QbT) approach, the product quality and performance are predominantly ensured by end product testing with limited understanding of the process and critical process parameters. Regulatory bodies are therefore focusing on implementing quality by design (QbD), a science-based approach that improves process understanding by reducing process variation and enabling process-control strategies. In this regards, pharmaceutical industry is currently undergoing a significant transformation to stream line their R&D process, provide greater manufacturing flexibility and control, and to reduce regulatory burden. However, there is a limited understanding and major concerns regarding the implementation of QbD principle in the pharmaceutical arena. The objective of this review article is therefore to provide a comprehensive understanding on various aspects of QbD, along with addressing the concerns related to its implementation. KEYWORDS: Quality by Design, Design of experiment, Quality risk management, Design space, Quality target product profile.