Yes. Chargify is officially Level 1 PCI compliant, the highest level of security a business can offer.
Chargify also works with your payment gateway's secure vault (i.e. Customer Information Manager in Authorize.net) to store your customer’s billing information in PCI compliant fashion. We work with your gateway so you don’t have to worry about managing this sensitive information.
Our services are hosted in a special facility that focuses on financial transaction security and integrity. You may be interested in our blog post about our hosting facility.