Artificial chromosomes (ACs) are highly promising vectors for use in gene therapy applications. They are able to maintain expression of genomic-sized exogenous transgenes within target cells, without integrating into the host genome. Although these vectors have huge potential and benefits when compared against normal expression constructs, they are highly complex, technically challenging to construct and difficult to deliver to target cells. This review focuses on the current progress in the field of ACs and discusses the recent advances in purification, construction, delivery and potential new molecular therapies.