Exhibit 21

PREFORMED LINE PRODUCTS COMPANY

SUBSIDIARIES

Domestic Subsidiaries:

Direct Power and Water Corporation

Albuquerque, New Mexico

Foreign Subsidiaries:

Australia

Preformed Line Products (Australia) Ltd.
Sydney, Australia

Brazil

PLP-Produtos Para Linhas Preformados Ltd.
Sao Paulo, Brazil

Canada

Preformed Line Products (Canada) Ltd.
Cambridge, Ontario, Canada

China

Beijing PLP Conductor Line Products Co., Ltd.
Beijing, China

Mexico

Preformados de Mexico S.A. de C.V.
Queretaro, Mexico

Poland

PLP-Belos SA
Beilsko-Biala, Poland

South Africa

Preformed Line Products (South Africa) Pty. Ltd.
Pietermaritzburg, Natal
Republic of South Africa

Spain

APRESA — PLP Spain, S. A.
Sevilla, Spain

Thailand

Preformed Line Products (Asia) Ltd.
Bangkok, Thailand

United Kingdom

Preformed Line Products (Great Britain) Ltd.
Andover, Hampshire, England