The changes were announced by prime minister Gordon Brown last year and patients can start applying as of Tuesday 20 January in time for the change which starts on 1 April.
Although good news for cancer sufferers, campaigners want the changes to apply to all patients and have called for all prescription charges to be scrapped as has happened in Wales.
The process is currently being phased out in Scotland.
Once patients apply they will be issued with a five-year exemption certificate, which can be renewed and gives free access to any drugs even if not related to the actual disease.
Forms are available from surgeries and oncology clinics and must be signed by a GP or doctor. In order for applications to be processed in time for April 1, forms must be returned by March 24.
It is thought this new rule could save as many as 150,000 cancer sufferers £100 each per year.
Peter Carter, general secretary of the RCN, said free prescriptions for cancer patients would ‘ease some of the stress and burden of a cancer diagnosis’.