What are the chances of making a one hour and half connection in Madrid Barajas?

In general if it's the same airline on both legs, they won't book the ticket if you don't have at least the minimum time. If you don't get more info here, there is at least one active Madrid airport forum on Flyer Talk: https://www.flyertalk.com/forum/spain-portugal-gibraltar/662473-connections-through-madrid-airport-19.html

Madrid is a very large airport and it can take quite a bit of time to transfer from an arriving international flight to an intra-Europe flight. I've missed one connection there and nearly missed another. Now I won't book a connection under 2 hours. If you do go with the 1.5 hour connection and the passport control line is long, look for the fast track line and ask the attendant to let you use it. Last time I went through Madrid, the fast track line was about a half hour faster than the regular line.

If your arriving plane is on time, and if there's no undue holdup at immigration or security, and if you have no mobility impairment or other reason to move slowly, and if you don't stop for any reason until you're at your next gate (no food, bathroom, etc), you will make it. If any of these are not true, you may not.

Assuming this is all on Iberia, here's what's involved. You arrive at Terminal 4S; you then walk a long distance to the shuttle train to Terminal 4. In Terminal 4, you walk a lot more to immigration. You then go through security, then walk a lot more to your next gate. I really am not exaggerating the walking; as Frank said, these terminal are humongous. You'll see signs throughout the terminal indicating approximately how long it takes to get to various other parts of the T4-T4S complex; these are accurate, but again, only as long as you don't stop moving.

I made a 2 hour connection with time to spare (to get a snack, use the bathroom, and await the start of boarding for my next flight). But my route (Madrid to Biarritz) only had one flight a day, so I was more worried. From Madrid to Rome, there should be multiple flights a day; if your arriving plane is late and that causes you to miss the connection, Iberia should put you on the next available flight at no extra charge, which should be later that day.

Personally I'd try for 2 hours, but if you can't get that, I'd make sure there was more than one other later Madrid to Rome flight that day, on Iberia, before booking this connection. If there isn't, definitely book a longer connection.

If this is not Iberia, you will probably use different terminals and I don't know the procedures or how long they will take.

I’ve taken Iberia MIA-FCO and my transfer time at Barajas was an hour. I made the flight with about 5 minutes to spare. It was a long, convoluted trek from one flight to the next. If there’s a hold up at passport control, seek help. When choosing a flight from MIA, sit toward the front of the cabin so you’re off the flight ASAP.

OP is on Air Europa. Its a T1-T2 change.

There are two later MAD-FCO flights so even if the 80 minute connection is missed, there are alternatives.

Personally I would have booked the 2hr 55 minute connection to give myself some breathing room

Tips - when you check in, in Miami, make sure that you have your boarding passes to Rome. Make sure your luggage is tagged through to Rome and that the agent also attaches "short-connection" tags. Choose seats near the front of the plane. Ttell your flight crew that you have a short connection - they may be able to help you get off the plane quickly and/or may be able to give you your departure gate. When you encounter a line in Madrid (security, immigration), try to find a staff person and tell them you have a short connection. Sometimes they will advance you to the front of the line, there may even be a dedicated line for short connections. Lastly, do not expect your luggage to arrive in Rome with you. Pack what you need for the first 24-48 hours in your cabin bag.

thanks.. I will make sure I get the tickets ahead of time, and I'm also thinking of taking my luggage with me. (packing light)