To get on the PhD track, the procedure is much the same as if you were applying direct from your first degree (i.e. the process and criteria are the same). As such, the more time you spend out of academia, the more you can weaken your chances. For right or wrong, work experience doesn't count for much, even in business academia so you are at a good point now to make the switch. [Hopefully] you have developed a decent awareness of how business works without having yet forgotten how higher education works.You'll want to look at which b-schools are good at research and open to academicians - these are not always the same as the top MBA schools. You'll generally have more and better opportunities if you take an academic MSc/MA, MRes or MPhil rather than an MBA en-route to your PhD.There was a full-page article in the FT last week, if you have chance to scan the Business Life/Business Education/Workplace sections. I don't recall the subject's name but he was being interviewed about his experience of switching from a career in banking to academia, including doing his PhD. The summary seemed to be not to leave it too late.