“What she describes is abhorrent and against everything Uber stands for and believes in,” Uber boss Travis Kalanick said in a statement.
“Anyone who behaves this way or thinks this is OK will be fired.”
The controversy is just the latest to surround the company, particularly on issues around the treatment of women at the firm.
Ms Fowler wrote that shortly after joining the San Francisco-based company, her new manager made sexual advances towards her.
She wrote: “He was trying to stay out of trouble at work, he said, but he couldn’t help getting in trouble, because he was looking for women to have sex with.”
Lack of diversity
After reporting the incident to Human Resources, Ms Fowler said she was told no further action would be taken as it was a “first offense”. She said she was told she should try and join an alternative team at the company.
From here, she goes on to list several instances where she felt poorly treated. She cites data – which the BBC has been unable to verify – that the number of female engineers at the company has plummeted over the past year.
Unlike Google, Apple, Facebook and others, Uber chooses not to disclose figures about diversity at the company.
On Sunday evening, Mr Kalanick responded to the allegations.
“I have just read Susan Fowler’s blog.
“It’s the first time this has come to my attention so I have instructed Liane Hornsey, our new Chief Human Resources Officer, to conduct an urgent investigation into these allegations.
“We seek to make Uber a just workplace and there can be absolutely no place for this kind of behaviour at Uber.”