The purpose of this study is to provide ZD1839 for those patients with locally advanced and/or metastatic non-operable non-small cell lung cancer (stage III or IV) or recurrent and/or metastatic squamous cell head and neck cancer who receive the therapy on an expanded access basis due to their inability to meet eligibility criteria for on-going recruiting trials, inability to participate in other clinical trials (e.g., poor performance status, lack of geographic proximity), or because other medical interventions are not considered appropriate or acceptable.

Inclusion Criteria:

• Have received at least one course of standard systemic chemotherapy or radiation therapy
• Are ineligible for chemotherapy or radiotherapy
• Are ineligible or not candidates for enrollment in available ZD1839 trials for NSCLC or squamous cell H&NC
• Are, in the investigators opinion, not medically suitable for chemotherapy.

Exclusion Criteria:

• Current eligibility (i.e., meeting the inclusion and exclusion criteria except signed informed consent) for any ZD1839 protocol available to the patient, or previous enrollment in a blinded ZD1839 protocol
• Patients from a blinded protocol may be considered for acceptance, with AstraZeneca's permission, only after trial completion and unblinding of all patients.
• Patients eligible for or previously enrolled in an open-label or unblinded ZD1839 clinical trial may be considered for acceptance with AstraZeneca's permission
• Incomplete healing from prior oncologic or other major surgery