Nanotechnology ant its applications has emerged as one of the central new technologies in the 21st century. In the last decade thousands of scientists and technologists are employed in this area, a great number of patents and scientific publications have been publishedAlarge number of new nanotechnology products have flooded the market of the developed world and inevitably large amounts of money are invested in Research & Development in themost advanced technological nations. Future prospects in different fields of nano-applications seemunlimited and its high potential will affect our daily life, our health and the environment in the years to come. Nanomaterials found applications in the fields of consumer products (cosmetics, textiles, diagnostic materials, personal care products, paints, etc), food, energy, medicines, computers, portable telephones and a great variety of other scientific fields. But in recent years, scientists and environmentalists are thinking about possible hazards to human health resulting fromnanoparticulate exposures in theworking environment, after contact with consumer products and through environmental pollution. The requirements for appropriate health risk assessment and safety regulations of nanomaterials are being explored.Also, environmental pollution and the fate of nanomaterials in the natural environment, especially in the aquatic environment, are some of the great concerns to scientists and environmentalists. In this paper we present an overall reviewof the current state of knowledge related to toxicity and human health risk of the engineered nanoparticles. The review presents the latest research papers on newchallenges facing scientists and technologists with nanaomaterials. Furthermore, the review examines the future requirements for making nanotechnology safe for the consumer, the industrial worker and less polluting for the environment and the ecosystems. Based on the current toxicological results, scientists provide a proposal on how risk assessment in the nanofield could be achieved and how it might look like in the near future.