Inclusion Criteria:

- Histologically or cytologically proven adenocarcinoma of the colon or rectum.

- Metastatic disease that is not amenable to potentially curative treatment.

- Measurable disease (as per RECIST 1.1 criteria).

- At least one prior chemotherapeutic regimen for metastatic disease. Patients must
have progressed following oxaliplatin based therapy (in either the adjuvant or
metastatic setting) and irinotecan based therapy (in the metastatic setting).

- Adequate bone marrow, liver and renal function.

- Patients receiving anti-coagulation treatment with an agent such as warfarin or
heparin may be allowed to participate, provided stability in anticoagulation therapy
is documented at the treating provider's discretion. For patients on warfarin, the
INR should be measured prior to the initiation of study treatment and should be
monitored at least weekly, or as defined by the local standard of care, until INR is
stable.

- Women of childbearing potential must have a negative serum pregnancy test performed
within 7 days prior to the start of treatment.

- Women of childbearing potential and men must agree to use adequate contraception
(barrier method of birth control) prior to study entry and for the duration of study
participation. Men should use adequate birth control for at least three months after
the last administration of sorafenib.

- Patients may have had a history of other (non-colorectal) malignancies if there is no
current evidence of persistent or recurrent disease and they are not undergoing any
active therapy (including hormonal).

- Patients should have paraffin-embedded tissue from initial diagnosis or prior
colorectal cancer surgery available for molecular analysis.

- Patients must consent to participate in the study and must have signed and dated an
IRB-approved consent form conforming to federal and institutional guidelines. Consent
must be obtained prior to any study specific procedures.

Exclusion Criteria:

- Prior therapy with a tyrosine kinase inhibitor.

- Age < 18 years

- ECOG Performance Status > 2

- Less than 28 days elapsed from prior radiation therapy, surgery or chemotherapy to
the time of registration.

- History of known brain metastasis. Patients with neurological symptoms must undergo a
CT scan/MRI of the brain to exclude brain metastasis.

- History of clinically significant cardiac disease (severe/unstable angina pectoris,
NYHA class III or IV congestive heart failure, symptomatic coronary artery disease)
or myocardial infarction, cerebrovascular accident or transient ischemic attack
within the last 12 months.

- Cardiac ventricular arrhythmias requiring anti-arrhythmic therapy. Uncontrolled
hypertension defined as systolic blood pressure > 140 mmHg or diastolic pressure > 90
mmHg, as measured on 3 consecutive pre-enrollment assessments, despite optimal
medical management.

- Known human immunodeficiency virus (HIV) infection or chronic Hepatitis B or C.

- Active clinically serious infection > CTCAE Grade 2.

- Pulmonary hemorrhage/bleeding event > CTCAE Grade 2 within 4 weeks of first dose of
study drug.

- Any other hemorrhage/bleeding event > CTCAE Grade 3 within 4 weeks of first dose of
study drug.

- Pulmonary embolism or any other uncontrolled thromboembolic event within 3 months
prior to registration or occurrence of deep vein thrombosis within 4 weeks of
registration.

- Serious non-healing wound, ulcer, or bone fracture.

- Evidence or history of a clinically significant bleeding diathesis or coagulopathy
(without vitamin K antagonist therapy).

- Use of St. John's Wort or rifampin (rifampicin).

- Known or suspected allergy to sorafenib or capecitabine.

- Any condition that impairs patient's ability to swallow whole pills.

- Any known malabsorption problem.

- History of chronic or inflammatory bowel disorders, clinically significant chronic
diarrhea refractory to medical management, or unresolved bowel obstruction.