Arnold & Siedsma

Arnold & Siedsma is a well-regarded patent and trade mark attorney firm in the Benelux. The firm has a strong team of European patent attorneys, with expertise in fields such as chemistry, biotechnology, electronics, and engineering. The chemistry patent practice grew in July 2020 following the acquisition of Belgian patent firm LC Patents. The firm merged with the Rouse Group in September 2025. Follow MIP's coverage of this firm here.

Notable patent practitioners: Paul Hylarides, Gerwald Verdijck, Steve Duxbury, Nele D'Halleweyn, Bart Laenen, Rogier Brouwer, Petri van Someren, Erik Bartelds, Martin Luten, Bart Jacobs and Remy Van den Bosch.

Notable trade mark practitioners: Joop Elzas and Sandra Bauwens.

Chemistry specialist Steve Duxbury is the managing partner.

2025

"Pragmatic, sensible advice and prompt delivery. I can trust and value their opinions."

"What stands out about Arnold & Siedsma's IP service is their professionalism, expertise, and client-focused approach.

"Their team combines deep technical knowledge with a clear understanding of our business goals, enabling them to provide tailored and strategic advice.

"We particularly appreciate their responsiveness, attention to detail, and proactive communication, ensuring we’re always informed and confident in our IP decisions."

"Their ability to deliver high-quality work while maintaining a collaborative and approachable style makes working with them both efficient and enjoyable."

Case studies show the firm handled patent filing, prosecution, and oppositions at the EPO. It also litigated before the UPC in a precedent-setting case for a medical device client. Patent trainees Hadewijch De Clercq and Julie Paddeu joined the firm in 2024.

Case studies show the firm advised on several infringement cases and handled a trade mark opposition for a dietary supplements company. Trade mark partner Karin Becks moved to Labels-IP in 2024.