Can an Ontario professional corporation amalgamate with another professional corporation?

Generally yes, subject to extra conditions on top of the ordinary corporate rules. The Business Corporations Act allows Ontario corporations to amalgamate and continue as one corporation, and professional corporations can use this mechanism as long as the amalgamated corporation still qualifies as a professional corporation for the relevant profession — meaning its shareholders and structure meet that profession's rules after the amalgamation, not just before it.

Because professional corporations also need a certificate of authorization from their governing body, amalgamating two of them usually means dealing with the regulator as well as the corporate registry: confirming the amalgamated corporation's eligibility, and in many cases applying for a new or updated certificate rather than assuming the old ones simply carry over. This is a common step when two licensed professionals in the same profession decide to combine practices into one corporate vehicle. Because both the corporate mechanics and the governing body's approval need to line up, it's worth having a lawyer coordinate the amalgamation filing and the regulatory application together rather than treating them as separate, sequential tasks.