Thirty percent of managers admit to regularly "ditching ethics" in the workplace, compared to 13% of other staff. The study found managers placed job progression as being more important than ethics.
It also found that non-managers (43%) were the most likely to they feel pressured into unethical behaviour.
CMI chief executive Ann Francke said managers need to re-focus on principles not personal gain.
"We've seen company after company fall foul of ethical scandals and the costs can be huge – not only financially, but in the damage that's done to hard-won reputations.
"It's time for employers to step up and confront unethical behaviour and commit to developing management cultures where strong ethics are rewarded."
The study found 60% of workers said they have witnessed colleagues acting unethically to get ahead at work, with managers (accounting for 61% of cases) more likely to be spotted acting unethically than junior staff (26%).
"No wonder their moral compass can end up pointing in the wrong direction. Organisations have to set clear standards for their employees, and managers have a particular responsibility to take the lead."
Other findings
- White lies are a constant in UK workplaces with almost one in three workers (30%) reporting they tell at least one white lie a day at work.
- When faced with an ethical dilemma at work, one in five people (19%) tackle it by following rules or guidelines.
- 10% help themselves to company stock for personal purposes.
