Nationally, the number of deaths in the UK as a whole failed to show a significant fall in 2011-12.
The figures prompted the Health and Safety Executive to urge businesses to rethink workplace safety provisions in the New Year.
A total of 173 workers were killed at work in the UK last year, compared to 175 worker deaths during 2010-11. More than 23,000 employees suffered a major injury. In Devon, four people were killed in work accidents compared to two in 2010-11 while 442 were seriously injured, down from 458.
In Cornwall, three died in workplace incidents, up from one, with 221 major injuries, up from 207 the previous year.
Another 2,202 workers in Devon and Cornwall suffered injuries which required at least three days off work compared to 2,366 in 2010-11.
Urging employers to make employee safety their top priority for 2013, Rosie Edwards, HSE's regional director for the South West, said: "Each year, instead of enjoying the occasion, families of workers in Devon and Cornwall who did not come home from work safely, spend Christmas and the New Year thinking of absent loved ones.
"Hundreds of other workers who have had their lives changed forever by major injury will be experiencing difficulties of their own.
"When put into this kind of context, it is clear why health and safety in British workplaces needs to be taken seriously.
"I urge employers to tackle the real dangers that workers face rather than focusing on the trivial or miring themselves in pointless paperwork.
"My New Year wish is that we can reduce the number of deaths and major injuries in 2013 and make the year ahead a happier one for many families," she added. Latest provisional figures show that nationwide, on average, six in every million workers were killed while at work between April 2011 and March 2012.
High-risk industries include construction, which had 49 deaths last year, agriculture with 33 deaths, manufacturing with 31 deaths and waste and recycling with five deaths – making up more than half of all workplace deaths in Great Britain during 2011-12.
The HSE is the national regulator for workplace health and safety. It aims to reduce work-related death, injury and ill health through research, information and advice, as well as inspection, investigation and enforcement. Information on tackling health and safety dangers in workplaces is available at www.hse.gov.uk
