Callens, Pirenne, Theunissen & C° offer broad technical expertise and deep local market knowledge in audit, tax, accounting, IT services, risk management and corporate finance, consistent quality and impeccable service to multiple industry sectors large and small, private and public, local and global.

About us

Since 1936 Callens, Pirenne, Theunissen & C° has been a major player in Belgium’s top 10 audit and accountancy firms with a strong sector-oriented approach. Known for the personal approach and integrity and independence the company is highly valued by its customers. In 2008 Callens, Pirenne, Theunissen & C affiliated with Crowe Global and now ranks among the 10 most renowned accountancy firm networks worldwide.

Building True Value Through Personal Commitment
Smart decisions. Lasting value.


Experts in your sector

The vast industry based competencies of our experts allows us to offer comprehensive solutions for clients seeking opportunities and avoiding threats within complex markets.  Our service and support empowers our clients to react quickly to changing opportunities and capitalize on emerging trends that affect their business.

Our Challenges

The need for organisational transformation may grow out of a variety of circumstances – such as a change in strategic direction, a merger or acquisition, or an operating system that has simply grown unnecessarily complex and costly.

The change journey must be effectively planned and managed, and the challenge of truly embedding change into your organisation should never be underestimated.

Callens, Pirenne, Theunissen & C° can help you develop a consistent and integrated view of change, and help you take a strategic approach that considers people and structures alongside business process and system implementations.

Our experienced professionals work to understand your challenges quickly and identify what actions will be required to deliver a successful transformation.