Louise McCabe, 57, received the comment from 29 year old company CEO Jack Williams during a heated discussion between the two.
The tribunal heard Williams viewed older people as "not familiar" with the IT sector, and thought of McCabe as a "menopausal woman".
McCabe was stripped of her role as company director at e-commerce firm Selezar, where she was a shareholder and founding director in 2014.
She was placed on gardening leave and eventually fired after raising concerns with Williams about how members of staff were being treated - which the tribunal concluded was the main driving force behind them asking her to leave.
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Williams told a recruitment consultant to find "a younger team member who was more in tune with a young tech start company" for the finance department.
Matt Jenkin, employment specialist at law firm Moorcrofts, said that age discrimination is just one of many claims the company may face.
He told HR magazine: "The comments made by the CEO do show that age discrimination is still an issue in the workplace with outdated and misinformed views on older people - and older women particularly - still a part of some employers thinking.
"With the remedy hearing listed for October 2022 it is likely, particularly given that age discrimination was only one of the many claims that Mrs McCabe was successful, that the company in this case will face a hefty financial penalty for its actions."
McCabe has successfully sued the company for age discrimination and unfair dismissal. She also had claims for breach of contract, unlawful deduction of wages, and detrimental treatment for making protective disclosures.
Jess Kuehne, senior programme manager for ageism at the Centre for Ageing Better, said that the case represents the ageism that still exists within workplaces.
She told HR magazine: "This ruling is a clear and reassuring reminder that age discrimination is completely unacceptable in the workplace – or anywhere else for that matter. Ageism is sadly still rife in the workplace, and the extent of its negative impact on employees who encounter it is still very much underestimated.
“The instructions for the recruitment company to look for a younger person to replace Mrs McCabe is indicative of the systemic ageism that is still so deeply engrained amongst some employers. The notion that older people are inherently unfamiliar with technology is a lazy stereotype – and one which has serious impacts.
Kuehne added businesses should steer away from language that makes assumptions about older workers when recruiting.
She added: “We recommend employers avoid age-biased language, such as ‘tech savvy’ or ‘recent graduate’ in their adverts, and challenge any assumptions they have about older workers’ skills to attract a wider pool of applicants. And it’s worth it – research has shown that a firm with a 10% higher share of workers aged 50 and over is 1.1% more productive."
