Networked laboratory analytical instruments including chromatographs, mass spectrometers, PCR systems and sequencers have become critical cyber‑physical assets. Their convergence with Laboratory Information Management Systems (LIMS), electronic lab notebooks and cloud analytics creates a large attack surface that traditional IT security and biosafety frameworks do not adequately address. This paper presents a multi‑layered security framework specifically designed for analytical laboratory equipment. Through a systematic vulnerability assessment across device, network, application, data, human, supply chain and cyberbiosecurity layers, we demonstrate that laboratory instruments function as high‑value, low‑security assets where integrity compromises directly invalidate experimental results. The proposed defence‑in‑depth architecture comprises eight coordinated layers: device security, network segmentation, role‑based access control, data encryption, operational procedures, continuous monitoring, vendor supply chain controls, and a novel biosecurity and data integrity layer that validates experimental outputs and tracks chain of custody. Scenario‑based risk evaluation shows effectiveness against calibration manipulation, ransomware, bio‑data exfiltration and PCR threshold tampering. The framework aligns with NIST Cybersecurity Framework, ISO/IEC 27001, FDA 21 CFR Part 11 and Good Laboratory Practice standards. Implementation guidance for resource‑constrained laboratories prioritises low‑cost, high‑impact controls such as network segmentation and access management. Performance metrics (mean time to detect, mean time to respond, system uptime, data integrity assurance) enable quantitative evaluation. Laboratory cybersecurity must be engineered as a scientific truth‑preserving system, not generic IoT security.