They do, I was 35 when I got hired by my current startup. But they are less likely to hire 35+ for many good reasons. A 35+ is more likely to be have a higher

They do, I was 35 when I got hired by my current startup. But they are less likely to hire 35+ for many good reasons. A 35+ is more likely to be have a higher salary demand due to more expertise and experience. An early bootstrapping Startup usually offer low salaries (although sugared with share options) and can only hire people very early on their salary ladder, or the ones who are not so good... A more successful Startup often able to offer better salaries and do hire 35+, however only few startups are successful. That is a good filtering. A not good filtering is that a 35+ due to experience will probably know that 80 hour weeks, crunch modes etc are counter effective and are less afraid of saying no. And therefore 35+ are less attractive to entrepreneurs who are looking for people to put in their entire life into the company as they do even though they only own a tiny part of it, if that. On top of this a 35+ often have families, hobbies, a life etc and rarely can/will do more than 40 hours per week and will not apply to startups job ads that quickly smells of continuous crunch mode.