(956) 447-8600 or (956) 447-0332
Weekdays: 8:00 - 5:00 Saturday: 8:00 - 12:00 Sunday: Closed

About Us

Our Philosophy
On behalf of Pedro J. Peñaló, MD, PA, we welcome you to our medical practice. At Weslaco Medical Clinic and Mercedes Medical Clinic, we strive for excellence in everything we do. Quality and compassionate patient care is our number one priority. Over the last 8 years, we have served the Rio Grande Valley with an impeccable degree of professionalism, the highest and most excellent standard of care, and a compassionate commitment to our patients. Our patients enjoy treatment by outstanding providers and medical staff. Our clinics run on a service-oriented philosophy and provide patients with the best access to improving their well-being. Our internal medicine physicians and providers specialize in the care of patients 18 years of age and older. Our practice provides a range of diagnostic procedures right in our offices and we also have admitting privileges to Doctors Hospital at Renaissance and Knapp Medical Center. Our patients benefit from personalized care while hospitalized, as we believe in providing the best, personalized medical attention at all times. Our welcoming staff is dedicated to providing all patients with the best experience.


Pedro J. Peñaló; M.D, FACP

Pedro J Peñaló MD, F.A.C.P is a Board of Manager, Medical Director, Chief Medical Information Officer and Chairman of Quality Assurance and Performance Improvement for RGVACO Health Providers, LLC. He has served these functions since the organization’s inception in 2012. A champion in quality and accountability, Pedro Joel, oversees the architecture and design of all quality measures framework for the organization. Furthermore, Dr. Peñaló provides medical and technical oversight in the development of the Quality Assurance Program for RGVACO. Additionally, he is intrinsically involved in providing technical assistance in the development of the software, one of the most important elements leading to the current success RGV ACO enjoys.

Moving to South Texas after completing his Internal medicine training in St. Barnabas Hospital in New York City, Dr. Peñaló ‘s drive to lead in the delivery of excellence in medical care moved him to form his own small practice. This enterprise has grown at the pace of his desire to be an element of change in the care delivery model.

Married and a proud father of 3 boys, Joel’s time is balanced between his relationship with his Lord Jesus Christ, his devotion for his family, his passion for medicine, his competitive rounds of golf, and his passion for New England’s sports teams.

Claudia C. Pierson, M.D.
Medical Provider

Board Certified in Internal Medicine

Maria González, FNP-BC
Medical Provider

Joyful, happy, and patient focused, matched with excellent training and valuable experience, describes Maria’s approach to her work as provider in our practice.

Jesus R. Guerra, FNP-BC
Medical Provider

One of the most fascinating rewards from working in the medical field is the fulfillment I get from helping people reach their highest state of health and wellness. After working in numerous ancillary healthcare positions as an undergraduate from 1990 to 2011, I finally attained a Master’s degree in Nursing from University of Texas – Pan American in 2012. A lifelong commitment to education led me to attain Board Certification as a Diabetes Educator as well. Such education and credentials ensure high quality care for individual patients, their families, and diverse populations. I really enjoy and feel a great sense of responsibility to provide upmost care for those I serve at the clinic.

Crystal V. Perez, FNP-BC

Born and raised in Mcallen, Texas, Mrs. Crystal Perez earned her Bachelor’s of Science in Nursing in 2008 from The University of Texas-Pan American.

After graduation, Mrs. Perez worked at the prestigiously recognized Doctor’s Hospital at Renaissance for 4 years before returning back to school to advance her nursing career. She graduated with a Master’s in 2013 with her Family Nurse Practitioner degree.

Mrs. Perez currently certified with the American Nurses Credentialing and is up to date with The Texas Board of Nursing, and is trained with Basic Life Support.

Mrs. Perez currently works alongside the premier Mercedes and Weslaco Clinic Under Pedro J. Peñaló M.D.
She is proud mother of Michael and currently lives in Mission, Texas with her husband Rogelio and Mother Magdalena raising her family.

Fernando Mendez, PA-C

My name is Fernando Mendez PA-C. I graduated from the Physician Assistant Program at the University of Texas Pan American in Edinburg, Texas on December 2013. I am a nationally certified Physician Assistant by the NCCPA and certified by the Texas Medical Board. I have been practicing Internal Medicine, Emergency Medicine, and Psychiatry for the last four years in the Rio Grande Valley. It is a great honor and privilege to continue my medical experience with Dr. Pedro Penalo and provide the best medical care for the patients at the Mercedes Medical Clinic.

Lilliana M. Soliz, PA-C

Lilliana M. Soliz is a Certified Physician Assistant in Internal Medicine at the Mercedes Medical Clinic with Dr. Pedro Penalo. She is a native of the Rio Grande Regional Valley born and raised in McAllen, Texas and graduated from McAllen Memorial High School. She went on to the University of Texas Pan American to pursue a degree in the healthcare field. In 2002, she earned a Bachelor of Science in Biology and a minor in Chemistry and in 2003 she earned a Bachelor of Science in Clinical Laboratory Sciences. Then in 2008, she completed her Bachelor of Science in Physician Assistant Studies at the University of Texas Pan American and a Master of Physician Assistant Studies at the University of Texas Pan American in 2009. After graduating she has been practicing as a Physician Assistant for the past nine years with experience in women’s health and family practice at Access Esperanza Clinics and in pain management with Dr. Tim Chowdhury. She is certified by the National Commission on Certification of Physician Assistants and has a Texas Physician Assistant License issued by the Texas State Board.

Blanca Aguilar
Office Manager