The findings are based on a sample of 478 HIV positive people, who had been diagnosed while in employment.
The discrimination occurs even though there are anti-retroviral treatments that slowed progression of AIDS, the researchers found.
At the time of their interview participants had all the knowledge about their diagnosis for an average of four years, and around four out of 10 had progressed to AIDS or severe immune deficiency.
In the study, the participants were questioned about the progression of their disease and how they were treated in the workplace.
The research showed that women and those who were less educated were the most susceptible to workplace discrimination.
Twenty participants reported that they had been discriminated against because they were HIV positive.
149 participants said that they had lost jobs while of working age. Almost one in three said their health had precipitated their job loss.
But one in five said they had been sacked, and around one in 10 had not had their contracts renewed.
Women with AIDS or severe immune deficiency were more than four times as likely to lose their job as those with less severe illness.
Those with lower level education, who reported that they had been discriminated against at work, were more than five times as likely to find themselves out of a job as those who had not experienced discrimination.
But this was not the case for employees who were better educated.
The study appears in Occupational and Environmental Medicine