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.

For patent protection work, the senior leaders in the firm are European patent attorneys Paul Hylarides and Gerwald Verdijck, who are based in the Netherlands. Another notable leader is chemistry specialist Steve Duxbury, who runs the firm’s Munich office.

Electronics patent specialist Nele D'Halleweyn is the prominent practitioner in its Belgian practice. She is now supported by biochemistry patent specialist Bart Laenen. The team is also supported by Dutch and Belgian qualified patent attorneys such as Erik Bartelds, Rogier Brouwer, Petri van Someren, Erik Bartelds, Arjen Hooiveld, Martin Luten and Bart Jacobs. Patent attorneys Raimond Haan, Yannick Philippaerts and Remy Van den Bosch are practitioners to watch.

For trade marks, the firm’s core team is based in the Netherlands, where clients will find trade mark partners Karin Becks and Joop Elzas. Sandra Bauwens is a notable trade mark attorney in Belgium.

The firm also has a legal practice which has grown steadily over the years. The legal practice is led by Michiel Rijsdijk and Remco van Leeuwen, both specialising in IP litigation.

2024/2025

"We know each other personally and they are very professional."

"They are quick, dedicated, good and fun to work with."

"They are reliable and very professional. You can trust that the information we exchange will be handled confidential and they are very reliable."

"They provide quick and sound advice. They are very friendly to deal with and provide quick and sound advice."

"They are responsive, thorough in their advice and reasonably priced. Very friendly and good at keeping advice simple and to the point."

"Provide sound advice, good recommendations and are quick to respond. They are quick to respond; providing easy to understand and sound advice."

Nichole van Roon

"She's a wonderful colleague, very practical approach."

"She is very professional, a super colleague."

"A perfect trademark attorney – very professional and a super colleague."

"Very friendly, good communicator, responsive."

Sandra Bouwens

"A very practical approach and super to cooperate with."

"Very accurate, very professional – a super colleague."

Robbert Keij

"Very friendly and very responsive."

"Very friendly, a good communicator, and responsive."

"Nice, easy to work with, quick to respond."

2022 client testimonials

"Excellent quality of the work."

"Excellent understanding of technical concepts, making it easy for us to disclose our inventions."

"Excellent understanding of complex electronic circuit inventions. The people representing the firm are able to very quickly understand our inventions and provide excellent advice on how to patent these."

2019 client testimonials

An electronics client said: “[The firm has] expert knowledge in RF power and reputation for high-quality work.”

The Dutch team’s patent case studies show patent prosecution, oppositions and portfolio management work. Clients include The Boeing Company, Trico Corporation, Ampleon Netherlands, Teledyne DALSA and Illumina. The team also provided patent litigation support to companies like Tobrix and AV Custom Style. Addick A G Land left the firm in 2019. Former managing partner and patent attorney Joost Grootscholten left the firm in 2022.